"Some people" are pretty much enough though for someone to maybe not feel welcome back.
Yeah, you go to matches, I'm very impressed (have a cookie) etc. but as we live in a world with lovely audiovisual technology, it is quite easy to reflect on things that you can hear and/or see.
Not really, no. Its entirely possible to think "this guy used to play for us and we'd probably be relegated two seasons ago without him" about an ex-player and then not boo him and still be a football fan. I've seen it.