Am I overreacting or ?

I've been in this friend group for two years or so and I didn't realize how problematic it was until I started talking to some other people about it. The reason I say this is because recently they were doing some questionable things. For example, in one of our group chats, a dude was sending some videos he found funny. I and two others found them enjoyable, but the rest of the group didn't like it. So they made a separate group chat with everyone but the dude in it and talked about how annoying they found the stuff he sent was and many other rude things. Which I thought was messed up because they could've just muted the chat.
Another situation was with a person that they just had a fight with where they started teasing them until they snapped and left the chat. They responded to this by calling them multiple times. It got awful one day when said person was having some personal issues and the others in the chat ignored their claims and took them as an excuse to keep quiet and not apologize. The person later called me about it and started bawling in tears. This made me leave the group chat, but a couple of weeks later they reached out to me and I told them that I left because of them hurting others. They said I was overreacting and that they were only just joking. They also said that they didn't want to hurt the guy's feelings so they made a separate group chat to discuss the videos.
I don't think this counts as joking because it's happened more than once but a lot of the others in that group who weren't involved say it's normal and I'm just being dramatic.