My point is not that these people don’t have the right to say it, but that government should not beexpected to promote one religion bashing another. Might as well let the Klan put up an anti-Catholic display. I’m not in favor of vandalism, but the content of the sign puts it well outside the legitimate role of government.
If you consider the public square “government”, government has no business with any religious symbols either.
If however you consider the public square “the people”, then you allow the people their freedom of speech, so long as the speech is not incendiary.
And if it is incendiary, you handle it through the process, not by having a legislator sneak in and tear it down.
A mob could have shown up and torn the sign down. I know that sounds counter-intuitive, but inciting mob violence would have proven that the sign was incendiary.