They do a pretty good job of getting out there. I used to see at least a handful of them almost daily on the street corner in Kennett Square.
Over all, these things are a good time for them. It's their Mardi Gras. Since up to now, nobody has opposed them, it's fun. Everyone hates America, just like you. You can say anything against America and everybody agrees with you.
It's fun, it re-enforces your self-image, so there's an attraction.
But when the counterprotests start, all that is in question and their numbers go down.
Remember, most are there mainly because someone else made up their mind for them in a poll result. Regardless of their own opinion, if there wasn't a 70% poll to back them up, they wouldn't risk it.