I can't find it, but Steve Barnes has said that no political movement is ever for equality, which I take to mean both that political movements aim for an advantage rather than equality and that the leaders of a political movement aren't looking to be equal with their followers. Neither of these imply that political movements are never trying to address actual injustices.

Were you thinking of "Affirmative Action Isn’t About Uplift"?

http://www.overcomingbias.com/2009/07/affirmative-action-wasnt-about-uplift.html

I don't think low status helps a movement become popular ever.

Low status might not help, but that's a different claim from saying that a movement for improving the rights of a lower-status group can't become popular for other reasons. We're not talking about a small low-status minority, or even a low-status phase that's generally thought to be transitory the way childhood or having no sexual experience is. Nor is it something that can be thought of being the person's own fault, like some people view poverty or alcoholism. We're talking about group that consists of 50% of the population and needs to implement society-wide changes if they want to improve their position. Feminism has certainly been unpopular among many men, but there were also enough women to make it succeed regardless.