A government sanction of a certain religious belief. And because there are multiple versions of the Ten Commandments, and nobody's ever talked about putting up all versions, it's also government sanction of a specific version.

A poorly veiled attempt to put religion in the schools even after it's been made clear that it is unconstitutional. If they were interested in a moral code, it would not be tough to create a secular one, but that is not being done. In one area, they didn't post the Ten Commandments, but their own code, and even that one had to mention God in it.

You can see exactly what it's all about if you try to convince them to put up a moral code from another religion. They'd completely refuse, showing that it's not about morals, but about Christianity in the schools.