Do you really want to put the government in the position of deciding which of **your** religious beliefs are silly and whether you should be allowed to avail yourself of government facilities and functions without violating them?
"But if it's just using the physical plant then it's different. What makes an idol an idol is how those seeing it feel about it. I am a Christian, but I don't let statues of religious significance to other religions bother me. It's only an idol if I choose to treat it as one. Otherwise it's just another pretty statue, or maybe not depending on what the statue is."
I agree with you, personally.
But the prohibition of Orthodox Jews from entering into a place of Christian worship was halichially decided (to vastly oversimply, by the Sanhedrin), and personal feelings aside, 'tis the Law for Jews (until such time as a comprable or higher "court" makes a different ruling) that entry would be a endorsement of polytheism, and thus violate the rule of having no God, but God.
Again, have no clue about muzzies, and doubt it is a true objection, as I have seen many muslims enter Churches.
Another factor is this, from down in the story:
The ACLU-NJ said it first complained about a West Side High School graduation at New Hope Baptist Church in 2005, but agreed not to sue when the district's legal director made assurances that the school district would avoid holding a graduation at a religious location again.
But in 2006, graduation was again held at New Hope. And the principal at the time even told graduating students that they would get two additional tickets for family and friends to go to the graduation, provided they also attended a separate religious baccalaureate ceremony for the class at a Roman Catholic church, according to the civil liberties group.
If those claims are true, you don't have a hair-trigger, sue-happy plaintiff, but a school district that has gone back on its word for a third straight year; and a principal who explicitly rewarded students for taking part in a religious ceremony. That's over the line.
As far as the church decor goes, I found a picture here. I don't see anything that would according-to-Hoyle constitute depictions of God, but it's hardly a generic meeting space. And I can't tell what's depicted on the side windows of the sanctuary.
Apropos of nothing, New Hope's choir leader is Cissy Houston, mother of Whitney and aunt of Dionne Warwick; from the number of microphones in the picture and the description of its "media ministry" on the church's Web site, it appears to be a media-savvy megachurch. I'm not saying that's a good or a bad thing -- just a little background.