That’s bullshit. Hot rivers can cool down reactors quite well (you just don’t want even hotter rivers for different environmental reasons) and so can closed cooling loops.

The actual reason against nuclear is that it’s economical insanity, always has been and always will. Everything else is just smoke and mirrors. Stories about imaginary reasons against nuclear out there are actually a helpful tool for the pro-nuclear side. They have something to easily debunk while also keeping the discussion away from the only thing that actually matters: the ridiculous costs.