Muslims have every right to dictate what sort of dress is appropriate inside their mosque. And if you're asking to be a guest in a mosque, or if you want to go to a Mormon temple, or a Jewish synogogue, PLEASE do your homework and contact someone before showing up in your thong bikini. It might just be that the local house of worship has standards that are different from yours and mine.
It doesn't follow, of course, that you should HAVE to go listen to the local imam, does it?
Apparently, though, if you're a schoolkid in Great Britain, it's mandatory that you go learn some tolerance. It doesn't matter if you're Catholic and are refusing to give in to the demands of your CATHOLIC school; you'd better dress up in garb acceptable by MUSLIM standards, make the trip to the local mosque and be respectful or you're considered a truant.
A few things stand out in this article. It strikes me as odd that the family doesn't have a problem with going to the mosque in the first place, and are "only" objecting to the dress code. Maybe I'm not catching something here... but I think the Muslim "dress code" is sort of part of the trip. You are going to learn about how others worship, and to do so, you must show respect for their building. It's THEIR building. You dress according to THEIR dress code if you go. Please do not say that you want to wear your school uniform and it's not fair that these Muslims actually have standards. Might I suggest that your real problem is with the school?
The school should not be foisting this on their kids. I don't care what the government standards are. There should be some way to skirt them, and failing that, you cannot in good conscience undertake the education of these young minds. You couldn't possibly pay me enough to teach children how to have sex with bananas and condoms or whatever it is they are teaching in sex ed classes. I could be persuaded to teach the children "sex ed," though, if I had a bit of leeway on the content of the lesson. I'd just tell the kids that there is a way to make babies that they will learn after they are married, and shame on you if you were thinking about it or trying to find out too much before then. Stop that. Sorry, no questions today. Please write a paper about "piety" for the rest of the hour. Pretty short lesson, but then, I'm awesome at boiling down those 45-minute lesson plans sometimes. But I could check off that I "taught sex ed" that day, couldn't I? Yep. I rock. :)
Now, I do wonder about this "teaching tolerance" thing and whether that works both ways. In the article, the mom states that if the situation were reversed and Muslim girls wanted to go to the Catholic school, that the school would oblige them in allowing them to dress according to their religious dictates. Um, ok... maybe... but they shouldn't have to oblige anyone if they don't wanna. Odd of me, but I'm thinking there isn't this big rush of Muslim applicants at the local Catholic school anyway.