What's the big deal? He is the better actor, he deserves the part.
Better actor is a very relative term. You wouldn't cast Steve Bushemi in a role intended for wesley snipes.
Right, this is what I'm talking about - it's 'not random' for Nick Fury to be black in the movies because he's already black in the comics (or one universe, anyways). But what about before Ultimate NF was created and made black? How is that not seen as a random change but Peter Parker is?
So you're saying they changed his race in the comics to get a bigger box office draw in film adaptations? All right, then why can't Peter Parker be another box office drawing black actor?
No, I'm not saying that at all. I'm talking about the casting for the films.
See the difference is, when they changed Nick Fury in the comics it was because they were creating a whole new marvel universe, whoever decided to change him figured he wasn't a major character, and so they could get away with changing him significantly. All the major marvel characters were changed too, but only in relativly minor ways (iron man is the same, he just has a different reason for being drunk all the time, spiderman was a teenager again, etc). Note that this is Marvel changing things, not the movie studios. Marvel, for better or worse, knows what they want from their characters and what people expect. They have the best grasp imaginable of the history and mythos of the characters. Hollywood made spiderman 3. I know which organisation i trust to make changes to superheroes.
Spiderman is a huge pop-culture icon, everyone knows who spiderman is, and can describe him at the drop of a hat. If they don't get a nerdy looking white guy to play him one of two things will happen:
1) He's the same character, but black (asian, hispanic, etc) which is pointless, and just change for change's sake. Why arbitrarily change his skin colour for no reason other than he's always been white?
or
2) He'll be "black spiderman" or whatever, and will be a different character but with spiderman's powers. Which is also pointless because at this point you may aswell just make a new character.
As I said before, you wouldn't make a biopic about Will Smith and cast Tony Jaa, or one about Albert Einstein and cast Morgan Freeman.