In my situation it's always the other way around. The only time I tell people I'm vegan is when they want to go somewhere to eat. Which in the USA is a lot of the time. All of the aggression comes from the other side though, not mine. But I have noticed that over the years the aggression has turned more into a curiosity and more people like to ask me about the diet. Some of the time they want me to bring them some vegan food to try. But online its a totally different story. Aggression and name calling always starts with the non-vegans. Everyone's got some story about how a vegetarian made them feel bad about themselves. So you met one asshat, I meet a lot of non-vegans that are turds on a regular basis, but I don't assume it's because they eat meat and I don't lump all non-vegans with that person. I bet that person you worked with isn't even vegetarian any more if they are that aggressive with their believes.