You don't have to like everyone. Liking or disliking someone is a personal thing. But do you have to do what you have to do regardless of likes and dislikes? Well, yes, you do. It's called being civil. Also because you really have no right to be rude.
I, like most others, have my own likes and dislikes. Especially when they are baseless(!), I try to be as objective as possible when dealing with um, 'dislikees'. Therefore, I expect 'to be done to as I would do unto others'.
There is a certain someone out there (quite inconsequential me thinks -- er, so the dislike is mutual, eh?) who I feel deliberately does subtle things to irritate or snub me. When I feel indifferent, I do let it pass, but being female, the hormones kick in soon enough, and then I retaliate.
Changing things I write, leaving out my name, etc. do NOT go down well with me. This is crossing the line. No matter that this is not my dream publication that I am writing for or anything...!!!
P.s. Am not 'chicken' about letting this character know -- have done so, but thought it worth a rant here!;)