1. The law doesn't mandate USB-C in particular, the port can change without the law changing

2. Nobody was going to add a second port for charging when USB can handle fast charging already. And if you need to charge in a damp environment then use wireless.

3. I'm pretty sure you can add a second port and the EU law doesn't mind at all

And assuming USB 2.0, how much cheaper do you expect a simpler port to be?