I think because it's the learned defensive reaction. What ends up happening is that you have someone who really hates fossil fuels who is more than willing to back policies that require a quality of life drop or a massive cost shift onto individuals to achieve 100% renewables. So whenever it comes up anything positive you say about renewables has to be come with the explicit caveat that it's not yet a 1-1 replacement.
It's one of those issues the overwhelming majority of people are on the same page about what we should do but at the ends you have "my livelihood depends on coal" on one end and "my life is insulated against the downsides of full-renewables so I'm privileged enough to have out of touch opinions" on the other and that's who shows up in comment sections.
We don't need to do that. But the media focuses on things like that and turns everything into some sort of weird argument that renewables are literally going to freeze gramma to death. Its overwhelmingly about emotion.
Its the same as what we see with EVs, tbh. Oh noes, what if you get caught in a snowstorm!? Imagine if 80% of the cars were EVs and they got stuck and there were... no chargers! Picture yourself freezing to death because of "those people".
Real world performance and goals are not correlated well with media hyperbole.
Eventually we have to get to zero net carbon emissions. But the worst case is just to create carbon based fuels from CO2 extracted from the atmosphere and use it in places/for uses which cannot be covered by renewable electricity directly (the far north, airplaines, ...)
It's one of those issues the overwhelming majority of people are on the same page about what we should do but at the ends you have "my livelihood depends on coal" on one end and "my life is insulated against the downsides of full-renewables so I'm privileged enough to have out of touch opinions" on the other and that's who shows up in comment sections.