So we should ban all people who have same thoughts with somebody shooting people? OK, we've just banned: Muslims, Christians, Hindus, Jews, Buddhists, Atheists, Communists, Anti-Communists, Socialists, Libertarians, Maoists, Trotskyists, Marxists, Environmentalists, Bernie bros, Republicans, Democrats, Independents... Pretty much everybody. Except for you of course.
If their members regularly go out and start shooting people in synagogues and mosques which their pathetic online 8chan friends cheer them on? Eeeeyup, boot their asses right out.
> If their members regularly go out and start shooting people in synagogues
But they do. Not all of them in synagogues and mosques of course, some of them do it on stadiums, night clubs, buses, trains, buildings, and some use explosives, poisons, cars, etc. But adherents of all ideologies above committed acts of murder. So, by your logic, every adherent of such an ideology should be banned. Or just those that visit 8chan? It's hard to tell these days.
