^Yeah, and the Star Wars
novels were "canonical" until new screen productions started contradicting them, and now we hear that Episode VII
will probably disregard the EU altogether. Canon is not some magical invocation that fans can rely on as an absolute standard of truth. It's all just made up anyway and the people making it up can change their minds about anything. Even onscreen canon can contradict itself all the time. So Chekov wasn't on the show in the first season? Who cares? We'll say Khan knew him anyway. So Data used contractions all the time up to now? So what? Now he can't use them.
Fans put all this energy into talking and arguing and worrying about whether one thing is canon or another thing isn't, as if canon were some important, fixed truth they could rely on, but it really doesn't matter that much. It's just a label.