> Which EU country reacted against Uber's predatory pricing when it was actually happening?

Bulgaria kicked out Uber for not obeying taxi regulations.

Sounds unrelated? Well it used to be a socialist dictatorship and laws are still written in a ham-fisted-yet-vague* way so that (1) you can't realistically obey them and (2) they can be used against anyone state authorities (or their friends) don't like.

So what's the actual reason? Uber was on its way to price taxi companies out of the market by offering better service at a price of €0.25/km.

* If you're from a developed country and this sounds like what your government is currently doing, you should start panicking.