Protests, marches, and demonstrations welcome a very broad range of participants. These people, like you, show up for diverse reasons: a personal invitation, membership in a coalition, a sign on a light post. Some of them didn’t know anything about it until they saw it for themselves, and then they decided to join in.
From your vantage amidst that crowd, then, you will note signs conveying messages you don’t fully endorse, often conveyed with words and images you would never use. Yet for your time together those are your signs too. You choose to identify with them for the sake of a larger movement and its aims.
Dogmatism kills resistance.
YoRocko! 
Thanks for this thoughtful post, Rocky. I especially like this part: “From your vantage amidst that crowd, then, you will note signs conveying messages you don’t fully endorse, often conveyed with words and images you would never use. Yet for your time together, those are your signs too.” Always good to remember that, though we are all humans, we are not all alike — and that’s the beauty of it when protesting (and elsewhere, of course). Plus, when we see things in a way we wouldn’t have thought of them ourselves, we often learn something.