Imo, I think the use of thug in reference to us is a means of characterizing the fear white/non-blacks have for us. The word is a blatant substitution for ****** and represents all of the stereotypical negative attributes associated with us, (dependence on welfare; familial dysfunction and OOW children; uneducated; violent; irresponsible and so on).
Now that was how non-blacks tend to use the word.
As for other black people...I take it as them simply wanting to assimilate with non-blacks with the whole "looksee I'm different than them". shyt could be a matter of them needing access for $$, associating whiteness with greatness or a combination of the two. There's also the KentTV crowd that sees women who flock to these "thugs" as a major issue in society as well
Like you said in OP, its internalized...and a major part of that is the sense of how our inferiority is seen and acted upon. The word simply sums up the overall sentiment held for us by ignorant and scared people.