"Twitter DOES care about protests because it will actually make them lots of money" -> NOT CYNICAL AT ALL
I think switching from Favorite is a good thing, as favoriting feels just personal, whereas a 'like' or a 'heart' is a public vote of support/appreciation. I do agree, though, that 'heart' is odd, but I can't think of anything else better.
I agree that this is going to be an issue going forward.
Hearts work well for things like family photos and cats--the traditional strengths of Facebook. But Twitter's point of differentiation was always live, rapidly developing news. Conferences. Sharp commentary. Leaks. Announcements. A heart is just not the right symbol in these contexts.
Going for the broader market risks weakening the core use cases, which set the platform apart in the first place.
(Not saying that favs worked as acks either, I used them as bookmarks.)