Reason for the tag: mentions of sexual jokes and comments made about minors and a situation involving minors

So me and my whole friend group are minors, I want to make that clear right now. I do not wish to disclose the ages of the people involved, but we all are the same age, very few with a 1 to 2 year difference, and we are all extremely close, with most of us being 15 to 16.

For context: So we have a large friend group which we share over the app Discord as we can't have a group chat with over 10 people, so we made a whole server as there's around 20 friends there. I was really close with my friend, let's call him J, and I have vented to him about multiple situations which he had also vented to me about situations.

In January of this year, we had to ban someone (we will call him O.N.) who is white for saying the n word in people's dms after he said it in our server and chose to give him a second chance. (We ran it by the members in the server who are black and they have the go ahead for the 2nd chance and he still proceeded to say the n word to people which we then got notified about it).

One of the people in the server who was close to O.N. made a document to try and get him back in the server. We will call the person K. The main problem started when K brought up a private situation involving my friend that was in a gc that involved me, O.N., J, and my other friend that I will call M. The situation with M involved him making a sexual joke involving an artwork that very clearly depicted a toddler as the main focus. (The artwork was of a toddler on his father's shoulders that I thought was adorable which is why I shared it.)

Now, I get triggered when sexual jokes involving children get made because my niece (who is extremely younger than me) got touched inappropriately by someone and sexual jokes involving children always made me uncomfortable. The situation with M for solved after a lot of yelling (and crying because I'm emotional), and I told J about the situation because he left the call we were in before the situation happened and then joined back after the fact. I was shaking and crying when I told him (when I get extremely uncomfortable I cry and shake) and J proceeded to even agree and say it was fucked up.

M apologized to me profusely and explained to me he didn't realize what he said until he processed the situation. It's been months since the situation with M, but it's always been something that stuck with me and him because he regrets it deeply and I have accepted the apology, and M and I hate to remember the situation because it makes him feel bad about it all over again and I get really uncomfortable to the point I don't speak to anyone.

Back to K, he tried to say that even though O.N. had made a joke that involved a little kid character that looked to be around the ages 6 to 9, that doesn't make him a bad person and that M should've also been kicked out when the reason O.N. got kicked out in the first place was because of racial slurs. Immediately I was able to realize that J had told K, and when I asked J, he said "I thought you were over it," and "I really don't see what I did wrong".

At this point, I was done with him because many times before I had forgiven him for things like making jokes about my insecurities such as my weight, so I blocked him. J proceeded to speak with one of my friends, and J said he wasn't sure whether he wanted to make an apology, and last night he finally realized how many times he's fucked me over and hurt me when I haven't made jokes about his insecurities or used him for a punchline at all. My friend spoke with me and told me that he would send me the apology if J even chooses to write me one, and M also has yet to receive an apology when he got an apology by K first sent to him through J.

M and I are hurt, and J even told one of his friends about it saying that I got mad at him because he told K "a joke" about what happened between me and M that triggered me, and that he thought I was over it. Now I feel like an asshole because I cussed at J when I found out and then blocked him, and I want to know if I was in the wrong for how I reacted.

So AITAH for swearing at and blocking my friend after they shared a private issue that triggered me to someone else as a joke?