The song itself is basically Meek Mill and Rick Ross using the names of 2pac's songs in the very context those songs were made to counter.
It's as if 2Pac's songs about what's really going on in the bowels of society and how they affect the people who in them have been turned into catchphrases for ignorance, totally ignoring the message behind the song, and everything 2pac really stood for.
It's almost the sign of the times and the tell-tale sign of just how accepted the ignorance is in rap music (and modern black young culture).
The concept of the song is orchestrated around the spirit of Tupac being in them b/c in that sense "Tupac is back". And to the, what is Tupac doing? He's riding in a car with stolen rims, selling drugs, impregnating young girls and leaving them, and celebrating walking around the hood with guns and being the drug dealer, using people to sell and smuggle their drugs, and doing it all strictly for the money with little regard for the consequences of their actions.
Meanwhile, I think one can make the argument that the thesis of 2Pac's catalogue is that he's just a man with flaws. Someone who has good qualities and bad qualities, but a person who ultimately wants better for his people through their own pulling of their bootstraps. And tells the stories of the realities of the hood and the daily struggles that people go through.
For example, look at the context of some of the songnames mentioned in the MMG song, and what they were actually depicting when 2Pac rapped them and notice how Ross and Mill are exemplifying the very ignorance 2Pac was trying to counteract.
All Eyez On Me -
In 2Pac's version, the song was about 2pac and his boys doing what their thing, but their haters and the FBI keep watching them, so they have to keep on top of things and be aware of their surroundings, so no one kills them.
Rick Ross uses it in the context of "i have money and everyone wants to watch me", and is accepting of the attention he gets. 2Pac's version was his wanting the attention off him.
Brenda Got A Baby -
In 2Pac's version, the song was about a young girl that gets pregnant, the guy leaves her, she get's scared, secretly has the baby, has no one to turn to, and throws it in the garbage.
Rick Ross/Meek Mill use it like "i got my girl pregnant". Putting them in the context of being the guy that got Brenda pregnant. Which means they're placing themselves as the guy who leaves the girl after she has his baby.
Picture Me Rollin'
In 2Pac's version, it sounds like he's just rapping about driving around in a slick car, but the way he ends the verse, you can see that it's more about how it's about him making it despite his adversaries, yet now that he's made it, it's made the reality of the conditions around him that much clearer. And that anything bad he's done, he's regretful for, even though it was to support those around him. 2Pac even says in this song "Flossin a Benz on rims that isn't stolen".
Meanwhile in the Rick Ross song, they take the exact opposite approach, and even say "...on some rims that are stolen". And use the song as a reminder that you shouldn't picture them any other way, other than riding on rims that are stolen.
And I know that Afeni Shakur was actually glad they made that song. But she's also sold everything he's ever touched. She probably even sold his dirty socks for a dime.
I just think that if you look at the legacy of 2Pac, in terms of the message he was trying to purvey, it was a counter to just about everything MMG raps about. And rapping that "Tupac Back" with respect to the ignorance they are exuding in the song and attributing it to them acting in the spirit of 2Pac is disrespectful.