Just seeing someone drink or eat pork should not be offensive (it isn't to me).
I have a problem with non-alcoholic beer and pretent-pork products - what's the point!
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[ This is just a minor rant - I don't see the point in pretend meat either, if you're a veggie - eat vegetables! ]
Culturally most muslims find eating of pork distasteful/disgusting - so it transcends a religious injunction. Most Europeans would be
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ed at the thought of eating a cat or a dog, or at the sight of people eating what they know to be a cat or a dog (or for many Brits, a horse) - this is similar to the feelings a Muslim will have vis-a-vis people eating pork.
I don't know many Muslims who would be offended at people drinking in a bar etc - so context matters here.
Cheers,
Shafique