Replace the word "cancel", though, with "pause", and re-read your statements again. Think about it, how many times have a character or team or series been "paused", or put on hold, or killed off to be brought back at a later time? Even Wolverine is going to die at last, and presumably be gone for at least a year or so, in order to revive the character. And Peter Parker was killed off, as well. Suddenly, not so ridiculous?
No, it's still pretty ridiculous. Killing off a single character isn't the same as shelving an entire corner of the universe for no reason other than pettiness. Even when they "killed" Peter Parker (which, as mentioned, they didn't really), it didn't mean they suddenly weren't publishing Spider-Man books.

Whatever they do with Quicksilver and Scarlet Witch in order to make them (and possibly some variation on mutants in general) viable for the MCU isn't going to suddenly rearrange the entire mutant corner of the comic world, especially since the movie isn't even finished being made yet.