Right, but the statement extends to the present state of mind of the writer. They're saying that they currently find the notion that nuclear energy can be clean or the cleanest as absurd based on their childhood in the infancy of the program.

Isnt it currently the consensus that nuclear energy can be one of the more clean energy sources? Because they seem to hold their childhood view that thats crazy

The problem with the PRC is that if you complain about things you can get in a lot of trouble. That includes issues like safety and pollution.