When Librarians Attack!!!!!!

I had an interesting experience at the library yesterday. I haven't been to the library as often as I like this winter, and so it was really exciting being able to go. Things looked up even more when I saw that they had Isa Does It. I have to give this library credit, for as much as I rail on this city, the library is pretty impressive. They have a decent collection of vegetarian/vegan cookbooks, and they even stay somewhat current. I go to check out, and I just am feeling so great because it's forty degrees, and I'm at the library, and then the librarian has to choose to be a dick. I won't say it ruined my day, but it was an unnecessary downer. The librarian must have noticed the word vegan in the title, and decided to kind of challenge veganism. She went on a diatribe of how she was raised on a farm, and she is of the mindset that a) animals were created to be eaten and b) if we didn't kill and eat the animals, what would we do about population control, they might outnumber us all! There were other annoying factoids that she threw in, but those two stood out, as I have heard those weak ass arguments many times already. What surprised/irritated me is other times I've heard this it's at least been part of a conversation where I offered up a vegan viewpoint, prepared to defend veganism. I wasn't prepared to have to listen to this at the library. I can only imagine some of the strange books people check out. I felt very uncomfortable, and I felt like this woman was being really defensive with me for no apparent reason. In the past I would have argued with her, and let it really affect me. I told her simply we would have to agree to disagree. I said as strongly as she felt about eating animals, I felt that strongly about not eating them. I then took my books, said have a nice day, and left. I'm going to let it go this time, but if that ever happens again at this library, I will be complaining for sure. I feel I should be able to check out books without having to defend myself with a librarian. For a long time vegans were the butt of tons of jokes, from the crappy vegan food to the weak, sickly way we looked and so on and so forth. Times have changed, we are strong and healthy, not weak, and we now have vegan cheese that can be eaten cold. We've come a long, long way, and if I'm not forcing my ideals down your throat, I certainly don't want anyone else's shoved down my throat. When someone tells me animals are here only for consumption, I just have to walk away. I've learned through too many hours of debate that people who believe that are capable of coming to a different conclusion, but it has to be when they are ready to have that light bulb moment. We only learn from those moments when we are ready and accepting of the chance to learn and grow.
I'm curious how other vegetarians/vegans handle unexpected defensiveness and confrontations?