Hate the sin, not the sinner. But don’t let your non-hate of the sinner be the reason you then skip over the sin. Sin is still sin. Even if there is a reason for it. In fact, all sin has a reason for it. That’s kind of the point - evil without cause is senseless chaos, and incredibly rare. Almost every instance of hurt, pain, injustice, had a reason for it. The reason does not justify it, nor clean over the negative consequence nor the act itself.
Sympathize with the sinner (I, too, might have done what they did in that circumstance). Maybe even empathize (I, too, can feel what that would have been like). But do not allow that to brush over the sin (maybe then what they did was not so wrong). It was wrong. That is the nature of wrong.
It is the realm of ethics (but really, religion) to say what is wrong and right - precisely because it is tricky to navigate. The Bible teaches that we should not judge a person’s entire worth based on observed actions (only God sees enough to know whether someone is going to Heaven or Hell). But it absolutely teaches that we should judge acts as sinful or not - starting with ourselves, and then at a community level for the good of the community.
I find myself tempted, often, to refrain from the last step. Perhaps someone does something that is clearly wrong, and hurts me (they lie to me, then steal from me). I will sympathize, and say that what they did is understandable and therefore forgivable (even though, it needs to be wrong in order to be forgivable). If it is a one-off event, I will brush over it. If it is repeated, I will possibly confront the person as a matter of pragmatism - things cannot go on that way, so I must change them. Then I will move on. But nowhere in that process will I call out certain actions for what they are - sins.
Interestingly, Christians are quick to label sin in their own life, and self-flagellate to alleviate their guilt and shame (when really the guilt is wiped clean, and confession is the main road to healing). Or they will label sin in clear and often politically-adjacent realms (gay marriage is not the sin - but gay sex is. But yes, they are not unrelated). What I am calling for here for is not more judgement of people (again, we are Biblically called away from this), but a depth of clarity around what is sin and what isn’t. Be mature not to think less of someone for what they have done, but also be mature enough to call sin for what it is.
Should one inject humor around sin?
I believe one should always be able to make a joke about anything, and that humor is a beautiful tool given to us to cope with some of life’s darkness. But that is different than always being able to make light of something. A joke can be wry, but spoken with weight. This is where I would put sin and suffering. One can make a joke about marital infidelity, or porn, or murder - but not flippantly, lest the audience confuse the humor for a condoning or a blessing. All sin has some hurt or damage associated with it - to forget that is to project a reality that is markedly false (a wrong in and of itself).
Maybe our histories should be relatable - but our present should not be. Otherwise we are living just the same as those whose lives have not been touched by Jesus, and in that way invalidate any transformative power of the Holy Spirit.