Your kids agree with you probably because you're a good parent. Kudos to you on that; nothing wrong with it. No brainwashing required; you feel strongly on the subject, they subconsciously want to please you, and so they agree. Also, I never said kids won't like older movies; I like the classics too that I watched as a kid. The pattern of behavior I described doesn't fully realize itself until after one hits 30, I notice.
Possibly you are correct. My kids are rather unusual, very independent. I believe it comes from being raised by a single parent, and grandparents. However, there are lots of things they disagree with me on. No matter how hard I try, I cannot convince them to sit through Wrath of Khan in its entirety. And believe you me, I've tried.
It's not nostalgia, either. It's a genuine like of the stuff you saw as a young adult. Even your one-off example of Aliens actually proves my point - I was young when that came out and I think it was awesome (saw it before I saw Alien, too). But I was old enough already to read reviews, and I distinctly remember the reviews of the day - some of them, at least - complaining that they'd taken the masterfully suspenseful Alien, done a lame sequel to it and filled it with action sequences so that you wouldn't notice what a bad movie it was. And who wrote those reviews? Old people that enjoyed Alien a whole lot when it came out.
Battle: Los Angeles is bad, of course. But then again, there's a shitload of bad movies from the late 70's and early 80's that you and I have already forgotten. A tangential point to my original is that every decade produces some great movies and a ton of bad ones, and the older you are, the more likely you are to pooh-pooh even the good movies from the current decade.
You know, the more I consider it, and consider all the post '00 films I've watched, the more I'm agreeing with you. It's easy to forget the old crappy movies when there's so many new crappy movies to bitch about, especially when todays crappy movies are generally just a rehash of stuff I saw years ago.
I still stand by my point that there is less character development in current films, though. There are numerous films from years gone by that, no matter how terrible I perceived them to be, still managed some semblance of character development. Today's films seem devoid of it, save a few rare films. Then again, my awareness may be limited. I'm a typical nerd with very few interests in genres outside the typical nerd domain, so this apparent lack may just be a condition of the films I tend to enjoy.
I would also like to express my pleasure at how you treated my post as a respectful discussion, rather than just calling me names and whatnot. It's a rarity these days and I appreciate such adult discussion. That and being told I'm probably a good parent is nice. I get so little praise these days, I'll take it anywhere - even from strangers on the 'net. :)