With all due respect, so what? I'm not offended by it, either.
Constitutionality is not dependent on what does or does not offend you. The court here specifically addressed that issue and found that the display did offend the plaintiffs.
There is no "transcendent" right in the Constitution to not be offended. At least not yet, but give them time and SCOTUS will find one.
I don't know if the ACLU wsa involved, I think it was. Basically with the All Criminals Love Us, everything decent and good offends them, and everything evil attracts.