Being against nuclear is massively stupid, to be fair.
There are good arguments for Nuclear but there are also some real problems with it, even with the newer smaller reactors available.
Firstly however there is only 1 permanent storage facility on Earth and thats in Finland and its only just opened. All other facilities are temporary, generally they are thought of as safe but after over 70 or more years of nuclear power we still only have one country with one permanent storage facility.
Even with the new CANDU and similar types of reactors the cost is massive and the timescale to build is very long. The reality is that in the meantime solar, wind, geothermal, wave etc etc are filling the gaps. In reality only the richest countries with decent population bases can afford Nuclear. We have very roughly about 200 countries on Earth and less than 1/5th can afford Nuclear.
War is a problem as we have recently seen in Ukraine, whilst there was no disaster in this instance the possibility with the worlds increasingly fractious relationships that a Nuclear power station becomes a target and lets not forget that once we have a major nuclear disaster the recovery is incredibly long. The risk might be pretty small but the consequences are huge.
One of the biggest problems with people who push Nuclear as a solution is they are looking for a single solution that solves everything. the reality is that the world will have to make use of multiple solutions to solve different countries economic and physical needs.
Some of the solutions are interesting, for example France has around 5 Nuclear power stations that are past their use by date and to replace those stations will take time. Recently France passed legislation that means any open air car park over 80sq meters is now required to have a solar canopy installed over it. This of course wont replace the Nuclear power stations output but its an indicator of the various solutions being put in place. Spain and Korea for example are putting solar panels through the centers of their motorways, India and California are putting Solar over there water irrigation systems. Spain has put wind turbines along one of its motorways making use of the draft vehicles produce.
There are solutions, the issue is mostly willpower and politics to act quickly with them. Nuclear is an easy to suggest catch all that in reality is a bit more difficult than just saying it out loud.