That remark is unfair. No one is happy 100% of their life. But I don't sit and watch Star Wars with a scowl on my face if that is what you're getting at.
It's also unfair to imply that a person who takes issue with creative decisions, casting, plot devices, etc with their favorite franchises automatically makes them a grumpy person, or somehow that automatically makes them a "hater" of the franchise. That is what I take offense to. Just because a person might have a negative opinion of something shouldn't make them a grumpy person. And hoping to discuss those elements with people who also enjoy the show shouldn't automatically be dismissed, right?
Maybe I am in the minority here in taking issues with certain aspects of Star Wars, but that should not degrade my opinion, right? To discount a person as "grumpy" just because they disagree with something is not fair. Especially since I express a much larger amount of joy over Star Wars than I do discouragement. I think that goes for a lot of Star Wars fans... even those who do not like certain elements of it, and discuss those elements openly on these forums.