Basically if you say to me that you care about climate change and then reject nuclear, I stop talking to you and taking you in any kind of seriously. Once you reject nuclear it’s just virtue signalling.
They may believe that non-nuclear alternatives are perfectly viable. "The sun provides enough energy to power the world's needs 30,000 times over"...and all that.
You might be mistaking disingenuousness with ignorance, or naiveté.
My favorite trick is if someone blinks twice in 10 seconds I know they ate something with garlic today.