“God hates the sin but loves the sinner.”
To make sense of this statement one would have to have a fairly sophisticated understanding of how this can be both true and false. The statement assumes a certain context and then an explanation within that context. It reminds me of the phrase, “God helps those who [cannot?] help themselves.”
The first question we must ask is, Who is the sinner?
Are we speaking about a non-elect person?
Are we speaking about a believer who is living by faith?
Are we speaking about an elect person before they come to faith?
Can God both love and hate the same person? If so, can we also say: “God hates the sin and also the sinner?”
Reformed theologians spent some time discussing the question whether God hates the elect before their conversion. The primary question is not what is God’s view of the non-elect – and even here we need to tread carefully since he can be said to love them in a sense (i.e., “natural love”) – but how does God view his elect before they come to faith in Christ?
God, who is immutable, does not, properly speaking, change his mind towards those whom he has set his love upon from eternity. It would make God mutable if he were to not love the elect before Christ’s death, but love them only afterwards. There is, however, mutability in the creature. God wills a change in his elect, but his will does not change towards them. As the medieval theologians (e.g., Aquinas) argued, God does sometimes velle mutationem (to will a change), but not mutare voluntatem; or mutat Deus sententiam, non consilium.
We may ask a more specific question in light of God’s unchanging love to his elect: How can we speak of God’s love and hatred towards the elect before they come to saving faith?
Taking as axiomatic that God loves his elect from eternity, we may say that God loves his elect with a love of purpose, but not with a love of acceptance (Charnock). Or we may use the old distinction between God’s love of benevolence (amor benevolentiae) and his love of complacency (amor complacentiae). Benevolence is the root of love; complacency is the flower of love. Thus God wills well towards his elect before faith but is only well pleased with them after faith. Or he loves the elect before faith to make them his friends, but after faith they are his friends.
However, there is a sense in which God hates his elect before they come to faith. Those who do not believe are under the wrath of God (Eph. 2:3). But, this must be explained judiciously. God “does not hate their persons, nor does he hate any natural or moral good in them” (Charnock, 3:345). In fact, Stephen Charnock suggests that Christ even loved the morality he saw in the rich young man. Any “tincture” of goodness God will love. For this reason, many theologians, beginning with Augustine, quoted Wisdom 11:24, “For you love all things that exist, and have loathing for none of the thing which you have made, for you would not have made anything if you had hated it.” But while God does not hate their persons, he does hate their sins since sin must always and necessarily be hated by God. God hated the practices of the prodigal son, but he still loved his person. God loves all of his creatures since they retain, to some degree, his image. If God hates the sins of believers, he certainly hates the sins of his elect before they come to faith: “If he hates sin in its weakness, much more in its strength” (Charnock, 3:345).
God hates sin objectively, and so his hatred of sin terminates upon the person. Ultimately, persons are the objects of God’s wrath, not sins in the abstract. Actions are not punished in the abstract but persons performing actions are punished. So there is a sense in which elect unbelievers are hated before they come to faith because their sins terminate upon them as persons: “no displeasure can be manifested without some marks of it upon the person that lies under that displeasure” (Charnock, 2:252). Thus, God hates their state (i.e., state of enmity). They are in a state of wrath and are thus objects of wrath until they believe. But God also hates the elect before faith “as to the withholding effects of his love” (Charnock, 3:346). Consequently, God hates the elect before faith “because, being in that state a child of wrath, the wrath of God abides on him, and the curses of the law are in force against him” (Charnock 3:346).
Nothing can make a creature, whether elect or non-elect, an object of hate or God’s curse except sin. God only hates sin. But as he judges sin – as he must! – the judgments terminate upon the person.
What this means in sum is this: God is able to both love and hate the same person, and in different ways. As Augustine said, “in a wonderful and divine manner, even when He hated us, He loved us; for He hated us, in so far as we were not what He Himself had made; and because our own iniquity had not in every part consumed His work, He knew at once both how, in each of us, to hate what we had done, and to love what He had done.” Naturally, when a person comes to faith they are no longer hated in any way, shape, or form. God will necessarily hate the sin in the believer, but he cannot hate the believer. Again, Augustine: “Seeing, then, that He hates nothing that He has made, who can worthily describe how much He loves the members of His Only-begotten?” To hate the believer God would have to hate his Son, which is an ontological impossibility.
As for our own reception of persons, we can also aim to both love and hate depending upon the person and the context. Consider, for example, the attitude of the Psalmist:
Psalm 139:19 Oh that you would slay the wicked, O God! O men of blood, depart from me!
 They speak against you with malicious intent; your enemies take your name in vain.
 Do I not hate those who hate you, O LORD? And do I not loathe those who rise up against you?
 I hate them with complete hatred; I count them my enemies.
Psalm 31:6 I hate those who pay regard to worthless idols, but I trust in the LORD.
Psalm 26:5 I hate the assembly of evildoers, and I will not sit with the wicked.
We can and must hate persons in a certain context, but in a different context we can exercise love towards a specific person. If I am in direct (or immediate) contact with an enemy I have a duty to love him:
Luke 6:27 “But I say to you who hear, Love your enemies, do good to those who hate you,  bless those who curse you, pray for those who abuse you.
Romans 12:20 To the contrary, “if your enemy is hungry, feed him; if he is thirsty, give him something to drink; for by so doing you will heap burning coals on his head.”
Exodus 23:4 “If you meet your enemy’s ox or his donkey going astray, you shall bring it back to him.
These verses highlight our duty of love in an immediate relationship involving our enemy.
In sum, we can therefore say:
Admittedly, this is a complex question. It only highlights why we have to be careful with our pithy theological statements that sometimes make their way into social media. In trying to bless others we can actually do a disservice to the complexity of certain theological truths and we can confuse people who simply do not have the various categories to make sense of a statement or qualify the statement appropriately.
What’s at stake here is God’s character; he is love. To simply affirm God hates sinners without also saying he loves them (whether elect or non-elect) impugns God’s being.