The vote wasn't about religious liberty, it was about codifying mental illness. Either this guy thinks his constituents are extremely stupid, or he is.
When Hastert was speaker, he put Shimkus in charge of the cover-up of scandals among R Congressmen, not the least of which was Hastert himself.
In turn, Shimkus staffer Davis did the dirty work and was appointed congressman as a reward.
Votes on things like this are considered in terms of their personal lives and how it will affect their careers.