Disliking something is fine.
Liking something is also fine.
Challenging someone's viewpoint (if you disagree) in a civil and polite manner is fine.
Insulting and/or name-calling someone because they don't share your opinion (opinion, not fact, all art is subjective) is wrong.
This is how we get toxic fan-bases. Don't agree with someone's opinion on a film? Cool, explain why, nicely, and move on. No one is forcing you to re-watch it. The same goes for people who like something. If you feel passionately about it, argue your points, nicely, see if you can change their mind. Don't force your viewpoint on someone who doesn't agree with it. For example: It baffles me how some people can truly enjoy all three of the prequels and even rank them above the new films, but that's my opinion, not a fact.
It saddens me this topic even exists, we're all fans of Star Wars at the end of the day, that's why we're all here.
TL;DR: Be mature & respectable when talking about films. Right now as a community, we're living up to the stereotype of hardcore Star Wars fanboys on the internet who aren't happy with anything.