The assumption that cops in the US actually care about someone posting swastikas is questionable. We already have lots of people posting about crimes on twitter accounts under their real names, and the cops very frequently don't do anything about it. A sizable number of the swastika posters are cops, too, as demonstrated by the periodic investigations into police departments that reveal those sorts of things.

P.S. Requiring someone to have a credit card doesn't feel like free speech absolutism to me. A pretty big number of people don't have the ability to make credit card payments. Do their voices not matter?