1. They define themselves with the flags of losers
White supremacists tend to use two flags as the defining symbols of their movement: the flag of Nazi Germany and the Confederate flag (YES I KNOW IT'S TECHNICALLY "THE BATTLE FLAG OF THE ARMY OF NORTHERN VIRGINIA" BUT LITERALLY EVERYONE ASSOCIATES IT AS THE FLAG OF THE CONFEDERACY SO GET OVER IT). What do these flags have in common, besides symmetrical designs and WAY too much red? Easy. They're the flags of LOSERS.
In an incredibly bizarre turn of events, white supremacists have decided that the flags of two of history's most famously abject losers are the kind of iconography they wanna attach themselves to. Sure, both the Confederacy and Nazi Germany had super-racist belief systems at their very foundations, but they're also notable for getting BRUTALLY beaten because they both sucked ass pretty bad.
White supremacists associating themselves with shitty losers? Who could have seen THAT coming?
2. Their heroes prove there's nothing "supreme" about their (or anyone's) race
It's kinda nuts to imagine that the greatest historical leader of the white supremacist movement is Adolf Hitler, a man who famously tested out cyanide pills on HIS DOG because he wanted to make sure they worked and didn't want to suffer too much when committing suicide. Hitler, for all of his powerful oratory and bluster, was a weak little wimp (and couldn't even grow a decent full mustache) who sucked at painting and who pulled shitty pranks and farted all the time. Also, he looked like an insurance salesman with a bad combover, so that should make everyone question his whole "master race" theory on genetics.
Who else are their heroic leaders? Richard Spencer, the guy currently famous for constantly getting punched and fleeing? David Duke, the former head of the KKK who wrote a book under a female pseudonym explaining how to give blowjobs and receive anal sex? Steve Bannon, the lumpy failed screenwriter who is currently being outflanked politically by Jared Kushner?
Every hero the white supremacist movement has holds one thing in common: they're utter failures as human beings (even discounting their inherently detestable belief systems) who are also largely ugly as hell. Seriously, how can you honestly say your race is genetically-superior when your hero looks like this?
"Genetically superior" people looking like waterlogged bloated corpses is a weird interpretation of the word "superior."
3. Their most famous heroes are ALSO ridiculous hypocrites
Strom Thurmond holds a special place in the hearts of white supremacists for several reasons - his virulent campaign against the civil rights movement, his longstanding record of the longest congressional filibuster in opposition of ending segregation, and for being a hilarious hypocritical racist (okay they probably weren't a fan of this last bit).
Yep - Strom Thurmond, infamous racist / terrifying zombie senator, famously fathered Essie Mae Washington-Williams...the daughter of a black woman who worked for his parents (and who was only 16 at the time). So not only was Thurmond espousing racist views and policies to denigrate African-Americans nonstop, but he was sleeping with and impregnating an (underage) African-American at the same time.
And in case you're looking for a more modern example (given there is nothing less modern than Strom Thurmond), look no further than Mike Enoch - the pseudonym of a popular alt-right podcaster and blogger who regularly espoused insanely racist, neo-Nazi beliefs - the usual mix of anti-Muslim, anti-African-American, and anti-Semitism...until it was revealed his wife was Jewish.
That's the thing about these people - they espouse hatred and ignorance and use their positions of influence in the worst possible manner, and they're NOT EVEN GOOD AT BEING RACIST.
4. All of their beliefs are based on gibberish and nonsense
Here's the thing: "race" is a completely meaningless term. There is no such thing as a biological race - we are all humans and part of the same species, and literally everything else is minor aesthetic differences that ultimately mean nothing. This has been the position of scientists since the 1950s, and yet so many people are insistent that "race" is a meaningful way to judge others.
Want to know how meaningless the idea of "the white race" is? What was considered "white" has been in fluctuation for as long as the term existed - it's pretty well known that in the earlier part of the 20th century, there was a good amount of racism coming from white supremacists against individuals of Italian and Irish descent. And even as of recently, white supremacists seem more welcoming to lighter-skinned people of Hispanic descent. The point is - it doesn't mean anything, except what racists WANT it to mean.
And even if you were the type to think it meant something, ultimately each individual's ancestry is open to interpretation: if 86% of your ancestors were members of what you consider to be "the white race," but 14% were of African descent, are you considered white? Well, we could just ask notorious white supremacist Craig Cobb, who discovered that was exactly his genetic mix.
What it all boils down to is this: THE ENTIRE BASIS OF RACISM IS STUPID. Hell, ALL prejudice is stupid - to judge individuals or groups based on arbitrary categorizations and biases makes zero actual sense.
Anyways, just thought we should get that one out of the way.
5. They get mad when you call them racist, even though they define themselves by racism
Listen - if you're going to espouse beliefs that certain races are better than others and that certain races should be discriminated against, that makes you a racist. I'm not trying to be insulting, that's just the actual dictionary definition of "racist." And yet, for some reason, people who are objectively racists get really mad when people refer to them as such:
Source: The Atlantic
Source: Raw Story
If you're a racist, at least OWN it a little.