Spend some time learning about the concept of the excluded middle[1]. It is something that will be useful on your life going forward, it might even save you a lot of trouble.

I am writing a post about that for my blog but it's still not there so ... check back later? Lol.

Anyway, in this particular scenario, a co-worker not being my friend does not mean we are enemies.

1: https://en.wikipedia.org/wiki/Law_of_excluded_middle

Not giving a shit doesn't mean being enemies. I think the one who needs to spend some more time learning is you ;)

Why would this bother HR? They don't give a shit about the coworkers either.