There's something to this, but it's also possible for shareholders to divest from companies that don't share their political views (in the same way that you can refuse to work for or buy from a company whose views you hate.)
To the extent that that's true, I'm not sure what the standard for "relevant to the original issue" should be. Taxi drivers are disproportionally Muslim and Sikh and disproportionally immigrants. (noted here: http://democracynow.org/stories/17050 ) Does that count as relevant enough? If not, what would? If so, what else would?
I think that protestors should be careful about their tactics, but I don't think they should have to invent ways to tie a protest's theme to its objective. We protest when our moral values are offended, and that's enough of a reason.
A narrow point: Trump is not Obama. It is possible that the differing reactions to their policies, administrations, and signalling are based in the actual differences between their policies, admininistrations, and signalling, not just from differences in the amount of hypocrisy their opponents engage in.