I know a lot of people like this stuff. I hate it. I can't express how much. Fantasy is fun, but I like reality. All the beauty and ugliness alike. I don't like listening to too much stuff like this.. Usually it's in sci-fi/cyberpunk type of circles though (where people are so lost they refer to their lives as "meatspace").
But idealists in general think this way. If they weren't such sweet, well meaning people, I'd punch them.
You know I also find an agreement with your position 
Yes, imaginationland can be contemptible to many. Mostly because it'll never be the exact reality that you will ever experience. But I think it still grasps (either explicitly or implicitly) the reality that everything you regard as reality currently, personally, in your life, will very very very likely not be considered reality 100, 1000, 10000 years from now. That the human of 2000BC would probably be utterly lost in the reality of humans in 2015AD, even if there's similarities.
Theory and imagination may run ahead of us, but I tend to think that they still help in forming new realities. Ones that future generations will just take as 'givens' just as much as you and I do.
I just don't want the new reality of Thedosians to be the bloody Qun.
Yes, optimists can be annoying. Yes, idealists can suck. But not all of them, and not in every way. The dreamers and thinkers of the past have achieved things (or at least led the way to the achievement of things) that past generations of realists just couldn't deal with, and would wave off because too many dreamers and thinkers bothered them.
I'm not trying to convince you though, because I still agree. Thinkers can be lost in their escapism and dreamers can be utterly insane. At least a strong dose of reality and tradition and conservatism (not just talking political here... at all even..) can be outright necessary to get anything done well.