This is a really good point.
How do we know thievery is wrong...or that murder is wrong...or that bearing false witness is wrong...because God's moral laws tells us so.
God's word also tells us drunkeness and debachery is wrong, practicing homosexuality is wrong, adultery is wrong...conservatisim generally finds these practices wrong because we believe God's word and in His perfect and righteous judgment of these things.
I don't understand why some consider standing up and saying we consider these things to be wrong and vote in a manner that reflects how we wish our society to be governed is wrong?
Simply because we have a voice in how our societies are structured doesn't mean we're imposing our morality on others...just exercising our rights (for now) to share our voice regarding the direction our society is takes....when asked.
Most of us are not going about blowing up abortion clinics or burning down gay clubs, strip joints and all the lovely "spas" that are prostitution fronts or trashing liquor and "adult" stores and such. We simply voice and vote our convictions...how is that "imposing" anything on anyone?
The basic reality is sadly....my rights end where another's right begin and for some reason...we as Believers are supposed to OK with forfeiting our rights....

... that it is somehow better and more acceptable in our society to infringe on our rights than for us to infringe on the rights of others. We're expected to be tolerant of everyone elses ideals...but our ideals seems to be of little value to others...
I guess we're the "smokers" of society. Someone's right not to breathe smoke supercedes another's right to smoke. It's all about whose rights are more valuable than anothers...so apparently our right to live in a moral society...is superceded by another's right to promote immorality.
And the thingy is...it's not OUR morality we support...it's God's standard for morality. So people who have a problem with us voicing our support of a moral society...don't really have a problem with us and our standards...they have a problem with God and His standards...IMHO.
And if one has these conservative values and convictions...and keeps them to themselves...never takes a stand to voice them...I guess that is their choice...and perhaps they may consider themselves a "closet" conservative.