I think it's the other way around:

Rejecting nuclear waste site is an easy and almost cost-free way of garnering browny points with the part of your electorate that has been indoctrinated into massive radiophobia.

https://en.wikipedia.org/wiki/Radiophobia

It is almost cost-free because in reality, nuclear waste is so low in quantity and so easy/unproblematic to store "temporarily" that it just isn't a real problem. Politicians know this. So they can play this game.

And once pressure builds enough you dig a hole in the ground like you always could have and like the Fins just did and start storing.

Yes, putting it in a swing state is a non-starter. But putting the waste in a solid red or blue state? Makes perfect sense.