It causes uncertainty and removes willingness in private business and citizens to lead the change. More and more will start considering it may be better to wait and move only when the risk is low.
Switzerland is considering banning EVs. Even if they don't, your car is banned if you can't charge it...
This is different from an oil supply issue. It's your government telling you to buy an EV than the same government (not a foreign one) denying you electricity out of stupidity.
Edit: Switzerland isn't banning EVs, more appropriate to say it's considering restricting EVs