Because, nobody's talking about what a word used to mean in eons past when nobody today was alive. All words evolve and change meaning over time.

The problem is, "thug" has not truly evolved to the point where everyone uses it as a slur, yet people want to accuse anyone using it of meaning it as a slur.a

Most people over 25 learned a version of the language where thug meant your common hoodlum, hooligan or crook. This Indian cult reference origin would be news to Obama or the mayor. 2pac comes along, switches the word up, a cluster of jerks use it to be racist, and now we all pretend to forget the we grew up with.