It is possible to have a stance on something, choose to act on it and still not judge others for not behaving in the same way. You do this by acknowledging that you still may be the one with the "wrong" stance (whatever that means) and by having compassion for others that may not have had the same insights you did.

There are also people trying to reduce their environmental impact (so also an ethical stance).

But there are some who have allergies, and it can be easier for them to choose a vegan restaurant to be certain there's no lactose / egg contamination.

Do you feel the same about people who believe in a religion other than yours (or any religion if you're not a believer)?