Why hard to ignore? Is the premise that everyone is ignorant of the special knowledge that only activists have and everyone should be forced to consume? Perhaps most people already know about the subject and are either already making their own changes or simply don't care. In both cases, hard to ignore activism does nothing to advance the cause and only serves to discredit the message by making it associated with unlikable and often seemingly unhinged activists. Of course if the purpose is to impress one's friends, mission accomplished.
The counterpoint to this is, of course, the civil rights movement, which forced the nation to see segregation and mobilized national support for immediate action.
Our moral systems aren't going to line up to the point I can deliver an answer that will satisfy you. The only moral tactic is pacifistic opting-out. Most activists are as evil as the people they are fighting.
