I wasn't first person in this thread to use the term boycott in this thread.
According to Wikipedia a boycott is
a form of consumer activism involving the act of voluntarily abstaining from using, buying, or dealing with a person, organization, or country as an expression of protest, usually for political reasons.
This seems to fit what the Trek people are doing. It does not say that lack of quality can't be used as the reason for the boycott. It doesn't limit the reasons behind a boycott at all.
I think they are refusing to see it for more than just because they don't like the movie. I think its because of how it messes with the original Trek Universe or maybe they can't stand the Spock/Uhura romance. But you'd really have to ask them for their reasons for the "boycott".
As for my boycott of Lucas, it is definitely more just perceived lack of quality. The PT wasn't that great, but I'd still buy the DVD's if it wasn't for how Lucas was treating the OOT and its fans. I'd also get myself the soundtracks of all the movies. I like the soundtracks. correction: I love the soundtracks. Yet, I refuse to buy them because of Lucas. If it weren't for how Lucas was treating OOT, I might even buy the SE, just to have both versions. So, even under your definition, what I'm doing fits.