Because they live near the Great Lakes, which tend to soak up temperature spikes and average them out, and they just had a maybe 90-degree F June and July, perfectly normal summer temperatures, while the rest of the world just got fried in a fuckin skillet.
It's much easier for them to believe the lies that they like the taste of. The people old enough to remember when winter meant WINTER in the 70s are all dying, so the younger conservatives think this is normal. Who's complaining about no snow shoveling? Not them.
Somebody Non-American very casually pointed out that the great divide in opinion on this is between the Red States, which all have economies based on carbon emissions, versus the Blue states, that do not. Obviously California's main export is entertainment and software, they don't depend on mining (or trucking, or coal, or manufacturing, or agriculture, or, or), like a lot of Midwest states do.
Ag is a huge greenhouse gas emitter, especially meat production, so anybody who makes their money off of meat doesn't want to hear any of this global warming talk. Even soybeans are grown in the US and shipped to Asia, so there go the boats, belching CO2 from bunker fuel, even if the combines are electric. Somehow even the damn soybeans manage to emit a fuckton of CO2.
Blue states won't see much economic hindrance from low-carbon policies, as their wealth is mostly "knowledge economy" type stuff, while Red states would have to take huge hits, one after the other, to bring national CO2 and methane emissions down.
The Red voter doesn't know any of that, on average, but the wealthy Reds do, and they control the propaganda the rest of them consume.
I don't see much of a solution, here.