I don’t even know what this means. Are you saying that we should expect propaganda to not work despite it working since the beginning of recorded history? If so, that is really dumb.
On your first point: And this would be believed by whom? Just as everyone credible firmly takes seriously Russia's claims that it attacked Ukraine to rid the smaller country of a Nazi threat to Russian sovereignty? Give me a break.
As for your second claim: So can hydro plants, causing enormous destruction. So? Secure the vulnerable asset, create defensive and preventative strategies. You don't go through life not building genuinely useful things because somewhere, somehow, somebody might aim to do them harm. The logic is absurd if taken to any other level. For example, I should never buy or build a house because some group of landless lunatics might coalesce and try to take it from me one day. Better to not have my own useful home in the first place then? Absurd.
Also, nuclear plants can be a target for plenty of states or groups that don’t have nuclear weapons like terrorists.