This is also covered here by “People make games”
My opinion about what I remember: Completely agree regarding the gambling accusations and terrible exchange rates (definitely a platform issue). The "game studio"/abuse claims seem a little cherry picked and fear-mongering, however (I used to be in a Minecraft community in which some strange things happened. Does it have anything to do with Mojang?).
It does seem like the Roblox ecosystem is currently designed to encourage and capitalize on bad decisions by minors.
It's too bad, I like the idea of an open world that people can develop and extend.