Easy to come across the wrong way online where if you said the same thing in person with tone and emphasis it may be ok.

I’ve fallen for that trap a few times and so now I even delete comments before posting as if I think “maybe my intent wont come across correctly here”.

I think the problem with the comment (the one starting FWIW) is it comes off a bit sarcastic even if you didn’t mean that.

Reflecting back might sometimes be useful, but your particular phrasing came across as condemnation. The implication, to my reading, was judgemental: you thought they were appropriately feeling guilty but seeking outside encouragement to reject that feeling. If you're going to try your hand at prodding someone to self reflection, a more encouraging tone may be more useful. Otherwise you risk wounding someone who, in this case, is already struggling with something.

Reflecting back might sometimes be useful, but your particular phrasing came across as condemnation. The implication, to my reading, was judgemental: you thought they were appropriately feeling guilty but seeking outside encouragement to reject that feeling. If you're going to try your hand at encouraging self reflection, are more encouraging tone may be useful. Otherwise you risk wounding someone who, in this case, is already struggling with something.