This matters a lot at the moment because we need to significantly decarbonize our economy and the same people have been staunchly opposing that.
It's certainly not just about who gets credit. I mean, there's also the question of whether other people's children's health is worth saving if it's going to increase a utility bill. Or the looming spectre of tax dollars spent on making someone else's life better, rather than one's own life.
According to him, that stopped being even conceivable the day Obama was elected and people like Mitch McConnell made it very clear to everyone in the party that there were to be no deals of any sort which could give Obama any sort of accomplishment, not even things which had previously been generally uncontroversial. It was apparently quite frankly stated that anyone who did so would have the national party and the right-wing media machine targeting them during the next primary as if they were a Democrat, even if it was something like getting something like a highway project in their state. They knew how Bush had been able to campaign for re-election on things like “No Child Left Behind” and Medicare part D which had only passed with some Democratic votes and were determined not to allow that to happen in reverse, just as we're seeing now.
Even if they did oppose, it would likely be on the grounds of the cost, which is worth it, but still a valid complaint.