It has nothing to do with the OS. It's for the play store. But again, a limitation of the OS would be something that the OS can't do, not the OS just refusing to allow hardware for business reasons.

Your opinion on rational is just as flawed. People should be able to make their own products. It's specifically pretending to be open to form a standard that multiple independent companies join in on, then unilaterally controlling that standard to make decisions for the entire market that's abusive.

There are many companies that do what Apple does and run closed operating systems on their own hardware. Apple built their market share on the strength of their walled garden providing an excellent development environment. It's not what a monopoly is. Controlling the behavior of hundreds of competing products is a monopoly.