It’s not personal and could be done for number of reasons, same way we are selective who we talk to irl, we could be selective online.
Ignore feature could prevent people from PMing you some strange things or prevent you from seeing their posts if you find them nonsensical.
I am pretty sure I am on some people’s ignore lists, I’ve no idea and they have their rights not to see my posts. Doesn’t make them bad people not wanting to read what I have to say. I don’t think I am that important
Sure everyone has value but you don’t talk to everyone irl so it’s only expected that someone wouldn’t want to talk to you on here or you’d want to stay away from someone. It’s not something you did, it’s just people have rights not to read your posts