Is it wrong to stand up for your ex? 21F, 21M

My ex and I were highschool sweethearts, as a result all my friends are also his friends. We broke up over a year ago but do to being in the same friend group we are unable to cut contact. Nowadays I just try to engage less.

My ex starred in some reel that involved several people and shared the same in our group. Instead of saying anything positive, one of our friends screenshotted a particular frame of the reel, circled his head and asked about hair loss. Now my ex suffers from pre mature alopecia as it is hereditary and has been taking multiple treatments for it for years now and it is well known among our group. I found it very distasteful to joke about someone’s insecurity. I condemn body shaming jokes in general and I don’t care if someone is your friend or partner. Don’t comment about anything if it can’t be fixed under five minutes. So I called her out on the same. I told her that it was rude af and eventhough she wasn’t serious with her comment, we need to be considerate whether the receiver would take it seriously. I also asked her how she would feel if I commented about something I knew she was insecure infront of a group. She fell silent and deleted the screenshot and apologized.

Now I would have done this for anyone so it isn’t a surprise that I also did it for my ex. But the rest of my friends seem to think that I should have kept quiet because me whiteknighting him would lead him on. He is still in love with me while I have moved on and acts like these show that he still has hope of getting back together. But I have had multiple conversations with him and made it clear how I feel about our relationship.

Should I just have left it like that and shouldn’t have stood up for him?

Tl;dr: Friend made a hurtful comment on my ex and I stood up for him. other friends think I m leading him on and giving mixed signals