10:12 AM PT -- Yo Gotti has weighed in on the situation, telling TMZ he has experienced similar discrimination at the Cosmopolitan, and other hotels in Vegas. He says, "It's a disgrace that these establishments continue to judge us by the color of our skin and our professions instead of recognizing our artistry and dedication to our communities."

Gotti states, "I stand with Meek Mill and all my peers in the hip-hop community that have been disrespected by places like the Cosmopolitan."

9:08 AM PT -- Meek's lawyer is doubling down, telling us he believes the Cosmo and other Vegas hotels are discriminating against black hip-hop artists and illegally circulating a banned list.

Tacopina says the properties are treating the rappers like dogs, and acting like it's the days of Tupac and Biggie all over again.

He adds that the video of Meek being denied and threatened is all the proof needed to show there's something seriously messed up going on in Sin City.

Meek Mill will file a lawsuit this week against the Cosmopolitan hotel in Vegas for ordering him to leave the grounds and threatening him with arrest, and his lawyer vows to destroy the hotel for its actions.

Meek's celeb lawyer, Joe Tacopina, tells TMZ, he will ask for "heavy monetary damages" for "lying and humiliating Meek," adding, "I'm going to take this place down because of what they did."

Tacopina claims there's a list of black rappers who are persona non grata at a group of Vegas hotels. Cosmo denies it excludes anyone because of race, but Tacopina tells us he's already identified 2 other rappers -- Yo Gotti and BlocBoy JB -- who claim other Vegas hotels have denied them because they're black rappers.

TMZ broke the story, Meek and his crew were going to see DJ Mustard Saturday at the Marquee Nightclub at the hotel but they were met by security as they pulled up and were ordered to leave, and if they got out of the car they'd be arrested for trespassing.

The hotel tells TMZ, they do not discriminate against anyone ... They wouldn't let Meek in because Marquee was at capacity and they had told him that before he left for the hotel. There are problems with the hotel's story. First, you hear a security guard in the video say they denied him because of a prior incident. Meek seemed baffled and repeatedly asked for specifics, but the hotel security guy wouldn't say.

There's also this ... Meek asked if he could go inside the hotel to get something to eat, but he was still denied. Presumably, the restaurants were not at capacity.

TMZ broke the story ... Tacopina fired off a letter to the Cosmo just after the incident demanding an apology and entrance to the club, but the hotel didn't respond. Tacopina says it's now game on.

Tacopina claims the Cosmo is scrambling now, coming up with 2 different versions of events, both of which he says are lies -- that Meek was involved in a prior incident, and he was denied because the club was at capacity.

Tacopina says, "Show us one other incident where a white individual was denied hotel club access or access to the grounds because Marquee was full?"

The lawsuit will allege racial discrimination under state and federal law as well as defamation.