Because elitists.
Never understood the mentality. I mean I fucking looooooove Predator, almost entirely because I freakin' love the creature's design. But if somebody cosplayed as a steam punk Predator, with a top hat, I'd think that costume was brilliant (as long as it was well done).
For the record though I also love Robcop but I think the new design for the remake looks shit. But then I guess there is a big difference between a fan cosplaying as an altered version of something they love and a studio making a movie for easy money and changing everything that made you love the original in the first place. That and the new costume somehow looks more like plastic than the original, which is almost impressive in a weird sort of way. I'm very aware with the knew film that it's just a guy in a suit, where as my mind could pretend the original really was a cyborg with a human face (even if the suit didn't always look like metal in all lighting), especially with the visor off and you can see how they made his face overlap on top of the cybernetics and the metal head - the knew one with his visor off just looks like a bloke in a helmet.
Edit: I like Robocop for more than just Robocop's design, but the new film looks like it's missing all the satire, charm, character, atmosphere and "soul" of the original. Although it might be unfair to judge from a single trailer.
Edit again: Sorry for the tangent there lol.