What's crazy is that the ToS is basically, "allow us, Amazon, to give you algorithmically higher prices- and if you try to circumvent that, you can't buy from us anymore".

I think the arguments for these kinds of near-monopoly companies being true market-driven capitalism seem more and more false.

The idea that Amazon will tell you that you don't even own the right to your own shopping experience tells you everything you need to know. Apple owns your device and Amazon owns the right to show you whatever price/product they want, regarless of your search intent.