I've personally dined with three vegetarians at the meals where they went to try the Impossible Burger for the first time.

It's dangerous to make blanket statements about what all vegetarians think. For example, on the question of why someone has chosen to be a vegetarian, I've heard a long list of different reasons, including: animal welfare, environment, their own health/longevity/energy, not liking the taste of meat, not enjoying the idea of eating an animal's flesh (even if it were ethical), their religion encourages it, and/or it's their default because they were brought up that way and have never tasted meat.