"There were also cases of hotel booking sites charging more and offering more expensive rooms to Apple users."
As the AC in the second post notes, that's a completely different, unrelated thing. Setting personalised prices for customers is not the same as monitoring the prices of your competitors and/or resellers. The former can seem unfair from a customer's point of view (from the point of view of one seeing the higher prices at any rate), but is not generally illegal and is ultimately just capitalism in action - prices are whatever the market will bear, and if you can subdivide people into different markets each one can bear a different price.
The latter is a different animal entirely - if a retailer monitors competitors and sets prices to be the same as them, competition is removed and you effectively have a price fixing cartel. Similarly, if a manufacturer monitors prices and punishes retailers who don't adhere to a "recommended" price, again competition is removed. Essentially, algorithmic price monitoring can lead to companies accidentally forming a cartel without ever actually needing to agree to anything, or even talk to each other at all, while on a manufacturer's part it can force retailers into such a cartel in a similar way even if they'd prefer to avoid it themselves.
If anything, while people might not like personalised pricing it's actually a solution to this issue, since it means matching prices to what you think a given customer will pay rather than to the price other retailers are charging. Only if retailers used identical algorithms operating on identical data would you get the lack of competition that is the concern here. Any issues of such personalisation, privacy and data protection being the obvious big ones, are an entirely separate matter.
Biting the hand that feeds IT
