Star Trek needed that to be said since there was a low point. Star Wars never had a low point, it doesn't need to be said. It was already made for a lot of people.
Of course, there might need to be some statements regarding the prequels.
It was said because Star Trek fans exhibit an unusual level of entitlement, and Abrams was demonstrating he had no obligation to pander to them. It was a political thing to say.
However, some seem to have mistaken it as some kind of affront and think that he was out to get them, which is, of course, somewhat ironic.