It is quite a thorny issue. Do we 'ban' all items which may offend or pose a health risk? On what basis - religion, health, lifestyle choice, diet, phobia... And where is the line drawn?
At nursery/schools, in the UK anyway, we do teach kids about religions, festivals, cultures, etc, so the children get an understanding of others' beliefs. A bring and share breakfast is a great idea to see who eats what - we have done this at school (for the whole nursery and school) and the kids really enjoy all the foods. No-one has ever asked for certain foods not to be brought (only nuts). The Saudi table sits happily next to the German one and noone has ever made a fuss about what is served.
A child brought up in a no-pork household will know from a young age that there are some things they dont eat for religious reasons. My friends little boy knew from very young that he wasnt to eat hotdogs as they just dont eat pork in his parents' country. No big deal and he would eat something else while his friends had hotdogs. Hopefully they are not taught that its because 'that meat is shitty and anyone who eats it is dirty'.
I don't know any muslim or jew (I have worked for jewish firms) who has made such a request (actually, we have served veggie canapes at functions to make sure noone drinks too much wine and picks up a prawn). In fact, we have been given booze gift vouchers by rather religious types in the family 'because we know you like wine and weren't sure what to choose'. I cook veggie or even halal for them when they visit because they are my guests, hell, I even cook meat for the carnivores.
They would be mortified if someone was to push a 'no pork' on 'their' behalf as it would be seen as rude and disrespectful. Their culture is all about being diplomatic (there is a specific word that I can't translate but it means giving the best to your guests with a genuine great big smile) and treating others with respect (would never say 'pork is dirty'). I suppose not every culture/religion/family is the same but that is my own experience.
I also agree with the idea that pork products slips into all sorts of items that you wouldnt expect! Cake and sweets for starters.