I'm pretty sure the actual second group is vanishingly small, it just seems larger because people in general don't know anything about anything so they will be vehemently against nuclear simply because they don't actually know that it's clean energy.
Similar to the "data centers use all the water" people. I saw a Facebook post with thousands of people raging against Nevada/Las Vegas data centers because they were being blamed for the region's dwindling water supplies - googled it and less than 1% of the water used in the area goes to the several dozen data centers. Seems to me like there's probably a lot of bigger fish to fry but I didn't look into it any further.
People are sheep. They jump on whatever bandwagon that happens to cross their path at the right moment. Almost everything people complain about they're just wrong about. It's actually insane scrolling on Facebook these days, it's just an endless stream of bullshit with hordes of NPCs raging about shit they know nothing about and every now and then there's a person with a functioning brain trying to spread some knowledge but it's obviously futile.
Most people can't tell you how taxes work even though they have been paying them their whole lives and complain about them constantly. They will happily tell you a bullshit story about "their friend" who passed on a pay bump because it would increase their taxes and reduce their after-tax income.
It's honestly so fucking frustrating. I mean nobody knows everything but as someone who has a decent overview of how the world works, who understands most important things at at least a basic level, it's just blisteringly obvious that the average person does not understand almost anything. They just got hooked into something at some point, somehow, and now that's their identity. Pretty much exactly like religion. Whatever cult they happened to be born into is obviously the only correct one, they'll ignore any and all evidence and arguments because it has nothing to do with reason. It's their identity and that's that.