During his interview on the Million Dollaz Worth of Game podcast, Young Thug explained why he considers Boosie to be a "real gangster." 

Young Thug explained that Boosie being in the streets since he was 12, not snitching and doing time in his case, and then beating his case is proof that he's a real gangster. He added that taking care of your kids and your family isn't gangster, because it's "what you're supposed to do." 

Young Thug went on to state that "you have to do something, life or death, to show your loyalty and show that you're real." He then shared an example, explaining that someone who does time to hold their friend down shows that they're gangster. You can hear his full explanation above.