It works the same when whites use the term "racist" for blacks:
"Thug" in its modern usage, as Sherman was saying, has come to mean a black person—generally a black man—who has committed any perceived infraction a white person can think of. "Thug" might have once described people actually deserving of the term—Wall Street swindlers or cops who harass and kill citizens with impunity. But now it's mostly deployed to attack the character of black Americans, many of whom have done nothing wrong but be offensive to a white person's sensibilities.
The next frontier:
Not allowing anyone to hide - and, especially, not behind taboos.
ADDED - because it reminded me of my interactions with the Hockey-loving racists at Lem's Comment Home:
"It kind of takes me aback. It's kind of disappointing. Because they know. What's the definition of a thug, really? [...] Maybe I'm talking loudly; maybe I'm talking like I'm not supposed to, but—there was a hockey game where they didn't even play hockey, they just threw the puck aside and started fighting. I saw that, and said, 'Oh man, I'm the thug? What's going on here?'"