Am I wrong for feeling this way?

POSSIBLE TRIGGER WARNING. So before I start, yea I’m posting anonymously because I’ll probably get hate for feeling this way but I need outside opinions so that’s why I’m posting. So a couple days ago my MIL shared with us that she was molested as a child by and uncle. Which is terrible and sad, but then she reveals that it is an uncle that they see multiple times a year a their church camp which we have also gone to as well. So for 30 years she never said anything and just let all her nephews and nieces and grandkids (including my son) hang around him with no warning about what he has done. I feel terrible for what she went through, but honestly I’m really angry that she allowed parents to think he was a normal caring uncle and unknowingly place their kids in the path of a child predator. My confidence in her judgment is gone. Anyway, they sometimes watch my son and they have this family friend that they have had for years and both him and his wife give me the creeps, but I have tried to ignore my gut for the past 6 years. After this whole thing came out, I feel like I need to specify that I do not want them around my son when I’m not present. I feel I can no longer trust my MIL to inform me of unsafe people and I’ve always had a bad feeling about this family. I don’t feel like taking any risks with my son. So I guess my question is, am I just over reacting? Is it bad to trust my gut? I don’t want to hurt my MIL feelings about her friends but at the same time I don’t feel like it’s safe for them to be around my son. I feel bad for being angry that she didn’t tell anyone sooner but it is just so upsetting that so many kids have been put at the same risk. Also, I should note that I did not and will not voice my anger to her has she has gone through more than enough, this has just been building inside of me and I needed to tell someone.

UPDATE: some of you have asked if the rest of the family know and yes they are working on telling everyone. I think the only ones left are the kids of the uncle and his wife. Also, I wrote down my thoughts and was able to write a letter setting boundaries for my MIL and FIL for when and if they watch my son again. Hopefully, this doesn’t cause a huge problem, as my MIL is prone to melt downs whenever I put me foot down on something. Thank you all for the responses. It really helped because I was feeling really alone and wondering if I was just crazy to see this as a big deal. My hubby doesn’t like talking about it so I’m kinda on my own as far as processing everything goes. Thank you for taking the time to share your experiences and opinions.