Initially, world was very nuclear-positive. Engineers envisioned nuclear power being the holy grail of energy technology and a foundation for our future. Extreme energy density and low price-per-watt of nuclear fuel promised an energy revolution - and for a while, it actually began.
Added to expand: add to this the boost of military. The Cold War required many countries to build up nuclear arsenal, and to make weapon-grade plutonium, you need to conduct uranium cycle - one that conveniently produces a lot of energy and can be used to generate power.
Then, Idaho, Chernobyl and much later Fukushima happened, slowly turning the world against nuclear as a dangerous energy production option. Association with nuclear weapons and Cold War didn't help, either.
In the meanwhile, renewables like solar and wind, which were initially prohibitively expensive, got more traction and investment, and as a result of new developments and economies of scale, they eventually managed to become cheaper than nuclear in most areas of the world, rendering nuclear power financially inefficient and thus largely obsolete.
Earth the planet is totally alright with everything we do. It's been through much tougher times.
We only endanger ourselves and other living creatures.