I don't believe that for one minute. I believe they are self serving and want their way regardless of the benefit or damage it causes.
You could make this argument for some of the high level politicians, but not for the voting base as a whole. This viewpoint is held by a lot of people on both sides and is one of the reasons political discourse is becoming less and less possible in this country.
I know a handful of people from this forum that are on the left/left of center, and I don't question their motiviation in the least. We probably disagree on a lot of major issues (or at least how to try to fix them), but I've never once gotten the sense that it was because they wanted their agenda pushed, even if it destroyed America.
It is ok to feel that the agenda they are pushing would be bad for America (the left feels this strongly about the right too), but that doesn't mean that the motivation for that agenda is from a bad place.