They don't have an interest in what their posturing will do to their constituents, nor do they understand the real role of government.
In a democracy, or representative republic such as we have, the "real role of government" is whatever the hell the majority of constituents of said government want it to be.
If conservatives get enough people to come around to our way of thinking regarding limited government, and that's what gets voted in, then that becomes goverment's role.
Same way with your side. If enough people think government-as-nanny is the way to go, then that's what we get. Of course, you love a rigged game, where the judiciary steps in and creates their own law by fiat, but be that as it may.
The American people as a whole get to decide. You and your little cadre of wannabe totalitarians don't get to dictate what everyone's "self-interest" is.