I think one or two folk could calm down with the 'vegans are all twats' shit...
They aren't, any more than all women are bitches and all men arseholes and all kids brats...
That said, YANBU - I think its more than fair to offer to carve and plate away from the table, and to ensure there are vegan options.
I am not vegan, or even vegetarian, I cannot cope with the sight of carving meat off the bone at the table, it makes me gip (and no I am not a hypocrite I dont eat roast meat either. I eat sausages, you can carve as many of THOSE as you like in front of me, its bones I can't handle!), so I think that's a really generous offer tbh!
As far as 'would vegans cook meat'... I know some who would if you'd provided it, some who would let you cook meat in their kitchen and lots who wouldn't do either because the smell makes them heave or because they would have no idea how to cook it properly.
I spent several whole days on holiday with a vegan and mostly we ate vegan, but I ate meat in front of her and cooked it in the same kitchen as her.. and diary too.. and NOBODY DIED (well.. some pigs did).