This is one of the almost uncountable reasons it's damn hard to just run a business these days. "Refuse them service", leftist mob attacks. Demand to serve them, as here, leftist mob attacks.
Yeah, this must have been back in the late 60s early 70s. I was just struck how that tactic has morphed into what we see today - entitled, privileged blacks projecting their racist hate onto others in order to justify their TNB. They also liked to use underage protestors for “demonstrations” because it looked worse on TV when they got their heads rightfully cracked.