There's not much trust in anyone who says nuclear is completely safe, "we fixed it now," etc. That shouldn't be the motto. But fossil fuel is already killing more people, coal puts more radioactive uranium dust into the air even, and that's before getting into climate change.
I think people who are anti-nuclear and environmentalist are wrong, but it's not an insane opinion to have. There's no fact you can point to that says nuclear is safer than renewables. I just don't see how the world is realistically going to switch to renewables. We've already seen oil companies use those as distractions from nuclear.
Nothing man-made is "completely safe". No such thing.
However, nuclear energy is the safest form of energy production we have.
By far.
And that includes Chernobyl and Fukushima.
People overestimate the danger from nuclear energy by incredible amounts.
That doesn't mean that close exposure to a running nuclear reactor won't kill you in short order. That's why we build these things with shielding. A lot of other things will kill you in short order if exposed to them: cars/trains in motion, for example.