I had no idea this scene existed and I'm shocked it wasn't cut at the script stage, it's awful and makes zero sense.
Why would quark seemingly drop everything on DS9 and go to the planet to start a new business? Why start it literally right where the Baku lived and not anywhere else on the planet?
Why does Picard act like he has the right to make any decisions when it comes to the planet? The federation and starfleet have no jurisdiction whatsoever, that's the reason Picard disregarded orders, basically told his superior officer to go fuck himself and started the titular insurrection in the first place and suddenly he acts like he gets to decide who gets to "bother" the Baku and who doesn't?
The planet is about to become a federation protectorate? Says who? How much time passed since the end of the battle? Did Picard contact starfleet command and the federation council, told them he kinda disregarded orders which led to the admiral's death and might have soured relations with the Son'A but it's okay because reasons and they all immediately folded and declared a protectorate? Doesn't that take time? Wouldn't details need to be negotiated with the Baku? And even if all of that happened at warp speed, Picard still said "about to become" so it's not yet, so Quark had every right to be dismissive of Picard. But even if the planet was already a protectorate, Picard still wouldn't been a decision to make decisions, the decision makers would be the Baku.
Did the Baku have an opinion on this? Who says they would be opposed to a spa or ten? Maybe not directly next to their village but they were generally very welcoming to outsiders coming in including the scientists who spied on them and the surviving Son'A, the movie literally ends with them beginning their reconciliation. But Quark building a spa is somehow a step too far? Despite his plan actually being way more benign than the federation's plan of kidnapping the Baku in their sleep and then making the planet uninhabitable?
"There will be no spas on this planet" ... Why not? What's the argument against them? Maybe not right where the Baku live but not anywhere else either? There could be 500 million visitors on the planet at once and the Baku wouldn't be bothered and could keep living their tech free hippie lifes. I don't know if the writers noticed but planets tend to be quite big and have lots of space. Even if we ignore the rest of earth, the american writers writing the movie should know from their own real life experience that most of their country is empty despite more than 300 million people living in it but somehow 600(!) people in one(!) village need an entire planet empty to be able to live their lifes in peace?
And then the line " ... which will end any and all attempts at exploitation by people like you". Seriously? Picard just fought his own people because they were going to exploit the planet in the worst way and he's already climbed back up on his high horse to look down on others?
If I had been a Baku in that moment I would have given Picard the sideway here, he's making decisions as if he's in charge of the planet and is randomly arresting civilians for wanting to build a spa?
The scene relies on the audience knowing that ferengi are generally greedy and have no problem exploiting others for their benefit but you cannot assume that but even with that knowledge Quark's plan is still the best presented to us.
Son'a plan: Destroy the planet, use the health radiation for our benefit!
Federation plan: Kidnap the Baku, then destroy the planet and use the health radiation for our benefit!
Picard's plan: Don't destroy the planet, health radiation for Baku only!
Quark's plan: Don't destroy the planet, build a spa, health radiation for everyone!
A truly awful scene, atrocious writing that makes everyone except Quark look like a douchebag.
Just because Quark is a great character, forcing him in doesn't actually mean it was going to be great. The scene would have been wacky comedy, in a movie where some of the humor was already not working. 
