Dumping is really only applicable if they are undercutting their prices in specific regions. If I am under-charging across my entire lineup, that's just on me.
Legality hasn't exactly been a problem to Uber's expansion. Why would this particular situation be different?
In quite a few countries, taxi rules are governed by cities - so the municipality government is the enemy.
Anti-monopoly/ predatory pricing rules are at least national level - and if you are unlucky you can go against the EU itself, which historically has not been afraid to slap companies with gargantuan fines that would never be allowed from the pro-business USA SC.
This is well above any fine from the EU.
Uber might feel that the risk-reward ratio is not good enough here to be acting in bad faith.
I doubt Uber is trying to run those cars with only one passenger at a time.