It's true: every denier is a worthless idiot, and the vast majority of those who accept anthropogenic climate change has a poor understanding of how and why it works. That's perhaps 90-95% of everybody discussing the question.
But there are still perhaps 5-10% of people who have at least a rough grasp of what's going on, and they're capable of actually discussing the real questions. Not the stupid questions, which are a waste of everybody's time, but real ones, like "how can we refine the models?" and "what are we going to do about it?" The latter may seem irrelevant, since government action is stymied by denialists, and individual actions are largely unimportant. (I'm glad you bought a Prius, and it is helping a bit, but not nearly enough by several orders of magnitude.)
Still... as bad as it is, stuff does get done. If we're locked in by chemistry and the suicide pact that our Constitution has turned into, we can at least take mitigating actions. The earlier we know about how agriculture is going to change, the better. We can take at least minor defensive measures for our flooded coastal cities. The US military needs to prepare for the various wars that are driven, in part, by climate-change driven poverty. It's even worthwhile to consider the "winners", like those Canadian farmers who will be able to take land that hasn't been touched and which finally has a growing season long enough.
It's not optimal; it's not even as good as is pragmatically feasible. But it's the best we can do in that paradox of democracy, where somehow all of us collectively are supposed to be smarter than the average of us individually. The majority of deniers and the majority of well-meaning but clueless (albeit correct) believers roughly cancel out and hopefully, hopefully it leaves a tiny minority able to do something that's better than not knowing at all. Thin gruel, but it's the best we can get.