What reasons do conservatives give for wanting to downplay Thomas Jefferson's role in Texas textbooks?

There have been many articles written about this issue,
and I have provided a few links for you.  Generally, the conservatives who oppose any
emphasis on Thomas Jefferson in the textbooks find it objectionable that he played a
significant role in the  separation of church and state.  He was also a Deist, which
means that he believed there is a God, but that he did not believe that any one
particular religion was better than others or that any particular religion had a direct
pipeline to God.  (I have included a link on Deism, too.) This is offensive to
conservatives, who believe that the United States was intended to be a nation founded on
Christian principles.  Can you see why a Deist who believed religion should play no part
in government would be someone conservatives would want to
de-emphasize?