Years ago I was walking with a friend and commented on some horrible PETA billboard, saying something like "their tactics do much more to turn off would be supporters than to help their cuase." She said, correctly, that I was wrong, that PETA's tactics probably don't do much to make people support PETA, but they are very successful at making people support the general cause of animal rights and welfare (if not all of the specific PETA microcauses). Almost everybody, upon being confronted with a gross PETA billboard, or some bizarre and unnappealing protest tactic, says "well, I don't agree with how they do things, but they still have a point." Whether or not PETA's approach is the best approach, or whether this is even how they think about what they're doing, I have no idea, but the point is that their approach probably is effective if judged in this way. It might not run up their membership totals, but it still works.
Crazy rude signs, bizarre performance art protests, minor disruptions of daily life due to protests, etc., might not enlist people in your organization, but that's very different from the question of whether they enlist people to your cause.