Memes

The harm is simple, people get the illusion they're making a difference and that it's enough, it also legitimizes voting as the way to change things despite ample evidence it doesn't.

This leads to Dems hating protestors, or telling protestors to protest quietly and no in the road. This leads to liberals hating the working class when they go in strike, because why didn't they just vote for better conditions. It leads to liberals hating anything useful, because they already did the only 'useful' thing and voted.

This leads to lesser evilism and accepting institutions as the foundation of society, instead of any ideology that will positively change things.