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.
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.