But to answer your question (sortof): you never have to, or should, apologize for what you like. And you don't have to explain yourself either. If you like a movie, that's truly a win-win. But outside of all of our individual likes and dislikes, there really are quantifiable ways to measure ability.
I just recently saw some YouTube clips of the guy who won Season 4 of Last Comic Standing, Josh Blue. He's got cerebal palsy. He's funny; you like watching him, and you want to root for him. But you can easily pick apart his "ability" and say he doesn't have particularly good timing, which is probably true, and that his jokes really aren't as strong as most pro comedians, and that's probably true, too. But so what? You laugh your ass off and you like him. So the sum is greater than the parts. But if all comics were Josh Blue, comedy would be taking a hit. Movies are the same way... there's nothing wrong with having virtually no story and all CG, and if you like it, that's awesome - especially 'cause you just dumped $10 on a ticket. But when most movies offer that stuff up instead of truly compelling stories and the execution of other craft, "moviemaking" takes a similar hit. Which is why you've got the studios talking about 3D, now. All of this, by the way, is part of a long-established Hollywood cycle. Back in the.. 40's I think... people stopped going to movies as much, and the studios had the same idea - gimmicks. That's where we got Cinemascope widescreen and surround sound from! Same situation today - they're trying to stop the bleeding with gimmicks instead of fixing the root of the problem. But it's okay, Hollywood is just in need of another enema and rebirth. We've been here before.
_Mike