It seems like this has been a recent-ish change of meaning at least the way I have always understood it. I admit to being of a "certain age" but the word thug never used to have any color associated with it. Thug could apply to white, black or green for that matter. But I do live in a bubble so maybe I missed something
1.a violent person, especially a criminal.
"he was attacked by a gang of thugs"
* - Sorry to Tajikey. It looks like we were posting the same thing at the same time