Not the original poster but I think they mean that the point of the law is to approximate morality and have it consistent across society.

If a court could look at a situation and determine that it is evil, then what is the point of determining whether it is legal or not? What if you came to the conclusion that something is illegal but not evil or evil but not legal? You pretty much undermine the construct of law in the first place and the existence of the court itself

The US government is prohibited from taking a position on religious questions. The nature of evil is such a question. The government frequently declares that something is "bad", but it is not able to declare that something is "evil".

Ah yes, for example the “Axis of Bad” [0] that then-President George W Bush famously named shortly after 9/11. Yes, that prohibition on the Government declaring things to be ‘evil’ is absolutely a real thing that exists in the real world in which we all live.

[0]: https://en.wikipedia.org/wiki/Axis_of_evil

Determining what is evil is not the exclusive privilege of religion.

You're silly.