Ya, I get this too... Whereas I like to follow the TAS community fairly closely, most of my other friends are mesmerized by Let's Plays and the occasional speedrun. It's a different story with them though because they all know how TASs are made; that it's just emulator input and that it could all theoretically be done on the actual hardware. The thing is, it's because they're familiar with emulation that they associate tools like save states with cheating; after-all, that's what most casual players use them for.
Well, there's that, and the fact that it kind of kills the nostalgia buzz when characters start flickering about at 60 Hz and glitching through walls and stuff. When most people watch gaming movies, they're looking for a sense of familiarity, something they can relate to their own experiences. When you start doing things a real player could never realistically accomplish it just doesn't jive with a lot of people's sensibilities about what gameplay should look like, especially when you start doing things like taking damage to save time besides.
Myself, I've always dreamed of being a game developers and its because I'm fascinated with what games are like on the inside that I like seeing TASers take them apart. That, and I admire cunning. The first time I saw a player taking damage to save time (in the Castlevania run) I was taken aback, but then when I saw them damage-boost I was struck by the genius of it all... Anyway, I agree that it would be helpful to publicize things like commentaries, strategies, tricks, game mechanics, etc.; anything to help more casual players relate TASs back to their own experiences playing these games.