Do you know what the First Amendment actually says, as opposed to your anti-Christian interpretation? Clue: it doesn’t say that Congress shall make laws prohibiting the free exercise of religion.
No, but it does say that government shall make no laws respecting the establishment of a religion. If Virginis posts a version of the 10 Commandments unique to a particular sect then they are establishing that sect above the others. And that is unconstitutional. And lest you think that this is my observation alone then let me quote James Madison: "Who does not see that the same authority which can establish Christianity, in exclusion of all other Religions, may establish with the same ease any particular sect of Christians, in exclusion of all other Sects?" - Memorial and Remonstrance Against Religious Assessments, 1785