Should you push arguments that seem ridiculously unacceptable to the vast majority of people, thereby reducing the weight of more acceptable arguments you could possibly make?
I think this is a tough call in general. Current morality would be considered "ridiculously unacceptable" by 1800s standards, but I see it as a good thing that we've moved away from 1800s morality. I'm glad people were willing to challenge the 1800s status quo. At the same time, my sense is that the environmentalists who are ruining art in museums are probably challenging the status quo in a way that's unproductive.
To some degree, I suspect the rationalist / EA crowd has decided that weird contrarians tend to be the people who have the greatest impact in the long run, so it's OK to filter for those people.