Don't we have pretty good immigration laws for hate-mongers? I can't find any articles cause I'm lazy and Google has gone evil, but a few times a year, some leader from some organization tries to get into the country to speak the "message" and CBSA gives then a polite "yeah, no, we don't allow hate speech here" or something similar... With the Nazi salute, I assume a case can be made for a "yeah, no"

Edit - autocorrect typo fixes