how much of an inconsiderate asshole am I?

So my best friend has an ex who we like to make fun of, because he treated her badly and his music lyrics are funny and bad. There have been 2 or 3 times where I've made fun of him and his lyrics with my other friends because I think it's funny; I only mention that I know who he is because my friend went on a date with him. The other day, my friend told me to stop telling people because it's funny but she had to actually go through it, and it's not other people's business. I apologized and told her I'd definitely stop and I get that it's weird that I'd say "lol I told my friend about him!" when he actually hurt her. I clarified that not to defend myself, but to make her feel better, I mention her to a tiny extent and mainly make fun of him. She said it's okay I love you so much and we're good. I still feel horrible and so inconsiderate that I'd do that in the first place. I care about her SO much. I know people have conversations like this all the time, but I feel like such a terrible inconsiderate ***, and I guess I could use some outside perspective on how big of a deal this really is. Is what I did objectively wrong, or an (extremely valid) specific boundary of hers?