Noone says you don't have to use nuclear. People say that building nuclear against climate change is an inferior intervention to fix climate change.
Actually Germans say that a lot and try to enforce it through the EU. They never found support for a complete ban but they're thwarting progress as much as they can.
And then you have the Austrians who try to cancel our nuclear power plants directly through activism, etc.
I read that debate about what is supposed to be green just a political struggle to get a larger share of pot of money distributed by being anti-nuclear they could "compromise to" natural gas being allowed as green.