I am sure all vegans and vegetarians want their food pure and suitable for them without the May contain labels.

I asked a few companies what does it mean when you state in you ingredients May contain eggs. fish etc ..they replied that it's made in a kitchen where eggs and fish etc are used for other food products but not necessarily in the vegan and vegetarian food products but made in the same commercial common kitchen. 
So the solution to this problem is all should have separate kitchen for making vegan only food produce ..a separate kitchen for vegetarian only food products ..and a separate kitchen for all other food products so now there is no need to put in ingredients label May contain eggs and this that and the other which is not suitable for vegans and vegetarians..this would not hinder sensitive vegans and vegetarians as they know their food is as it should be without any May this and that ingredients.