it turns out to be the present day, but they pretend to be in the 19th century for some asinine reason
It's not asinine. The village founders were operating under the "golden age syndrome," and felt that the violence and evil inherent in modern society could only be overcome by turning back the clock to a purer, simpler time. The point of the movie is essentially that they were wrong, or at least that their main aspiration (to keep evil and violence out) was (and is) unachievable.
Pretty good story, actually.
And don't forget the self-indulgent cameos in every movie- hell, even shyamalan himself told the main character in Signs how to defeat the aliens!
Why is this a problem? And why would it "ruin" his movies? Alfred Hitchcock gave himself cameos in most (or all?) of his movies. Does anyone think that that "ruined" them? Peter Jackson gave himself cameos in all three LOTR films. Does that detract from your enjoyment of them?
Seriously, dude, sometimes it seems like you're just looking for things to gripe about...