I'm not an activist. But when it comes up in conversation, I'll discuss it.But what they did to Alien with the reprehensible and reviled snuffing of Newt, Hicks and Bishop was loathsome to me; an abuse and violence done upon the franchise itself and perhaps to the character of the little saved girl too. What they did to Star Trek was *nothing* like that and deeply respectful and entertaining in comparison.
But surely it's easy to pick examples like that from any franchise? (Off the top of my head, the killing of Kirk in Generations or the racism of Code of Honour.)
Isn't the best response simply to go on and just ignore the part you don't like, as Greg has suggested, instead of going back to dredge it up so you can "officially" ignore the part you don't like?
To be clear, I wasn't talking about conversations. Heck, we're having fun dissecting fifty-year-old episodes every day.
I was talking about the actual movies and series having to establish "officially" what's still in the continuity, as though there's an office somewhere, complete with a notary public, that can revoke a movie's status as canon. When it comes to making the future movies, you don't need to rule that, say, THE FINAL FRONTIER isn't "canon" anymore. You just never mention Sybok again if there's no need to.
Doesn't mean he's been stricken from the continuity. Just means that nobody is in a hurry to bring him back anytime soon--or put him on the cover of a novel!

Or, to cite another example, even if the Prime Universe comes back, don't expect to ever see a sequel to "Spock's Brain" or "The Way to Eden." They may have happened, but they're not likely to inspire any future stories.