I recently had lunch with a group of people including one young woman who was a vegan. She said that she often received negative, even hostile, receptions from people she worked with or others in social settings when they found out she was a vegan, even though she was not a proselytizer about it and even if she mentioned it only in passing during casual conversation and it was relevant to the conversation.
I had noticed this before. For some reason, some omnivores seem to view vegetarians and vegans as a threat to their own values and often try to convince them that meat eating is better for them. Playwright George Bernard Shaw, a vegetarian who lived a very long and healthy life, amusingly described this odd response (quoted in Bernard Shaw: His Life and Personality by Hesketh Pearson (1961), p. 171):
When a man of normal habits is ill, everyone hastens to assure him that he is going to recover. When a vegetarian is ill (which fortunately very seldom happens), everyone assures him that he is going to die, and that they told him so, and that it serves him right. They implore him to take at least a little gravy, so as to give himself a chance of lasting out the night. They tell him awful stories of cases just like his own which ended fatally after indescribable torments; and when he tremblingly inquires whether the victims were not hardened meat-eaters, they tell him he must not talk, as it is not good for him.