Obviously the labelling applies to processed food.
Yes!
Although, on past form on this thread, posters will still come back asking "humorously" if:
apples
water
pulses
grapes...
are suitable, if not explicitly labelled.
I've never come across a thread like this for wilful misunderstanding on both sides.
And intolerance.
I had no idea it was such a heated debate.
I said before that I gave my ex-veggie, newly vegan DC a Cadburys Dairy MILK Easter egg. Always used to be her favourite. I know! The clue's in the name - colour me stupid 
As soon as I realised, I replaced it. She just said that she knew it would take time for non-vegans to adjust and, in the meantime her vegetarian boyfriend had benefitted.
It sounds as though from the OP's second post, a similarly civilised line was taken:
I am not A or B in this scenario, I am another guest. Just want to say that neither was actually outright rude to each other, my post might have come across that way as I was trying to keep it short. B actually was very apologetic that she could not eat it. And A certainly did not expect her to just eat it anyway. The issue came from A thinking B should have informed her of all the products she could not eat and B saying that was actually thousands of things that were not clearly meat and fish, including quite a lot of wines and beers.
that A and B both behaved perfectly politely.
A didn't expect B to just eat it (though sounds as though she may have been miffed secretly that her best "vegetarian" efforts had been turned down).
B apologised that she couldn't eat it (and may well be more upfront with omnivores in the future and maybe felt hurt that A hadn't researched more).
If some of the more militant posters here had been present it sounds as though WW3 would have erupted.