Well, there's two parts to this... I've been meaning to make a topic on this for months now, but I guess I'll just put the gist of it over here.
First, I have to say I don't think it's KS abuse. I don't doubt people do have good intentions. I don't doubt they really think they can make a game. Heck, it always seems so simple when you're thinking about it - but the technicalities creep up on you, and there's a lot more to game development than just starting to type out code. What I think is that, as potential Kickstarter backers, it is up to US to decide what gets funded and what doesn't. As long as there's a "market" for dreamy eyed fellows who have never coded anything but think they can do it, they're gonna use KS! If nobody funds projects from people without portfolios, well then, you'll start getting projects from people that HAVE portfolios. It really is that simple. I've made a conscious decision to entirely stop backing projects from people who don't have some serious portfolios. If you haven't walked the walk, I'm not going to fund you... not because I doubt your sincerity or your intentions, but I do doubt your capabilities. The problem isn't so much becoming greedy as it is actually MAKING a game.
This is becoming particularly true as new engines like GameMaker and Unity allow you to quickly hack together something that looks like an initial game. The problem is that behind the scenes, it's spaghetti code all over the place, and impossible to extend properly. As you add more and more duct tape to hold new features together, you get very strongly diminishing returns on the time you're investing into programming the game, because everything is breaking apart.