There is a healthy dose of pragmatism. Probably, very few people would choose nuclear if there were loads of alternatives, the capital cost and build times are insane and despite improvements, let's not pretend that nuclear fuel is easy to deal with.

But take away gas and coal and you are left with the green alternatives like solar, wind and waves which all have their own challenges the first two have high variability and aren't great for base-load and the third has challenges building equipment that can survive the extremely harsh ocean currents for a period of time that will not leave a trail of rusting relics (afaik).

I think it's more to do with the fact that the rhetoric around climate change has shifted. Now the official Green Party stance is that it is the most urgent issue of our time and must be combated by any means necessary. Of course, this conflicts with their (former) anti-nuclear stance, and they've been repeatedly criticized for this hypocrisy. I've even heard young environmentalists speculate that the Greens were secretly in bed with the oil companies.

Not just aging out, idealism as a political motive is essentially dead, because it's a luxury that can't be afforded anymore.

The new green line - everywhere - isn't "nuclear bad", it's "act on climate change or everybody, including your kids, will pay the price". The entire board changed, figures and strategies notwithstanding.