Laziness is one thing. UR I agree, is just plain retard looking, but to assult the way someone has always used their language by comparing Color and colour is going overboard.
American English is NOT the same as British English.
This is appearent in calling the hood of a car a bonnet, which to an American is a hat for a woman and a hood with has 2 meanings, the car's engine cover and the hat piece attached to a sweat shirt, a coat, or similar garment.
Black English is somewhat different, too, and I would not fault them if they spelled something fo' instead of for.
Please be open minded when you talk to people, and be sure you are not assaulting a culture rather than just laziness.
Thanks