How can you call any of that "punishment" or anti-competitive?

Steam offers the far superior platform, in every possible aspect. Every thing you've said is them OFFERING (not FORCING) better solutions to things.

For example, in what universe do you think it's sane to think a store front should accept random reviews from random people? Having bought the game is the one of the best metrics to tell if a review is even approaching sincerity.

Not having random reviews in the steam reviews is a feature.

And in the context of Android or iOS, the PC gaming market is SUPER DUPER EXTRA diverse. I own games in like 5 different stores, but always prefer Steam or GOG where possible.

Offering better services and getting more user because of it is not malicious or anti-competitive or monopolistic. It's the best possible outcome (assuming you like capitalism).