For me the easiest tell is the up front, unprompted, and unsolicited declaration of nonpoliticalness. When someone takes the time and expends the breath to announce how nonpolitical they are, what follows is almost always a rant about how everything/everyone else is too political these days, and that of course leads into something between status quo advocacy and outright reactionary/regressive sentiments for some fabled time before those wicked politics were visible to the nonpolitical ranter. 
People that are hostile to service workers. Some just want to take some ideological stand against tipping when the service worker doesn't really have a choice and needs those tips to survive in the current unjust system in a way where ideological purity gestures toward that service worker just look like being a greedy and sanctimonious asshole. The worst of such people will actually declare, shamelessly, that they believe that service workers don't deserve a living wage. The implications of that are 
worthy.
I may get shit for this, but I'll say it anyway: this hair and beard combo, seen on living people. 
I have yet to meet anyone in person with that look that wasn't a chud.
(If one of you is a comrade with that look, I am sorry in advance for the prejudice and if I ever meet you in person I will atone by buying you a drink or something.)
I dunno, in my experience European racism is a more primitive type that you don't see as much in America anymore. Like even the most feral American hogs usually do the pretend song and dance that racism is bad before they beat the insert slur here to death. Like not saying it's better, just the pretension that Americans are somehow uniquely racist seems like eurolib cope to me.
I think it is that racism is so baked into American society that it is hard to miss I mean a nearby country club, which cannot be turned into public housing fast enough, had to be sued to let in Irish Catholics in the 1980s so it is harder to deny here. As aresult more Americans are aware of their racism than Europeans.