“Capitalism operating normally” is often unacceptable as well. This is one such case. At best, they screw over a few people with no public backlash. There should be backlash.

It’s because despite what economists believe, prices are not determined fairly by the market but are dictated supply-side. So this kind of “testing” is one of the more blatant ways in which consumer trust is violated in the name of maximizing profits. It makes it obvious that you’re not paying a fair price for a service or product, but a price that was dictated for someone else’s convenience without taking your interests into account at all, violating the social contract.

So your argument is that because there are some exceptions to a rule, the opposite of that rule is true.