And what is your evidence of that?

I've personally been accused of being a neo-nazi on reddit because my username includes the number 88, which is only there because my wife's birth year is 1988 and I'm not creative enough to think of a unique name. I've seen the same frivolous accusations thrown around here as well.

The bar is so low that Jewish (like Stephen Miller) and even black (e.g. Ben Carson, Candace Owens) people are frequently called white supremacists. So low that people saying "It's ok to be white" were called white supremacists.

Does the term have any meaning now, or has it become simply a slur for anyone whose political beliefs differ, like "communist" or "terrorist" before it?

Agreed that there's risk in overuse which can lead to numbness for the real thing.

In some ways, I'd argue we should then be even more vigilant because white supremacist rhetoric / apologist sentiment and actions are having an easier time to hide behind the veils of fuzziness.

One comment though: you do not have to be white to be a white supremacist. White supremacy is the belief that white people are superior to people of other races, and should thus dominate them.

We see this pattern in other arenas too, e.g. gays and homophobia or women and gender bias.