There is no inconsistency.  I don't celebrate laws or this law, I support it.  It is wrong to legislate morality because it ends up with greater injustice.  Adultery is a serious wrong and it should not be a crime.  Idolatry is the most serious sin a person can commit but it should not be a crime in the U.S.  

We don't prohibit murder, theft, discrimination against blacks and women as a matter of morality but of public equality for all citizens which enables the public peace to be kept more readily.  We don't criminalize adultery because it would not cure the problem any more than illegalizing abortion has lessened abortion rates in any countries where it is illegal - it has in fact given these countries higher rates of abortion in almost every case.

There is a reason to have governmental laws to keep the peace and allow an even playing field for all citizens.  Churches have a higher criteria for morality as to what constitutes sin as this should be based on Gospel to gain salvation.