Number 2: Booking.com has always demanded that any room sold by them cannot be cheaper anywhere else. Every third party seller demands this. Hint: You don't have to sell all of your rooms through booking.

This rule could destroy booking.com depending on how it is enforced, since hotels could then just use them as a free advertising platform.

Number 3: Seems fair.

Number 4: They've always done this.

Number 5: They don't own any hotels AFAIK

Number 6: What do they mean?

All in all, it seems the regulators do not understand at all what they are regulating. After decades of online reservations being the norm, hotels should only blame themselves if they've become dependent on third parties such as booking.

Yes.