Earlier quoted context omitted.
Such a difficult thing to regulate. The instant you stop Amazon from selling on its own platform, they will open a subsidiary Amazon Retail, which is a favored customer on their platform. Whatever new regulation you can come up with, there will be armies of corporate lawyers ready to satisfy your requirements while still capturing that audience who is ready (and wants) to be captured by a platform-branded generic opt…
This seems a bit defeatist. We've successfully regulated against vertical integration in the past.
If it is possible to create a so-called firewall [0] within banks to avoid unfair advantage via insider trading, it is possible to create a firewall between the platform and seller divisions withing Amazon for a similar effect.