How to be "social" at work when the conversations are constantly about animal cruelty?

I am required to be social at my work. Have to attend lunches and maintain good rapport with everyone. It is not like most work places where it's nice but not a requirement; if I don't maintain a good image/rapport, I will not be able to do my job.

The problem is, so often the conversation ends up being in some way about animal cruelty, whether it's about eating meat or raising animals for slaughter. When the subject comes up, all I can do is paint on a smile and refrain from opening my mouth, because I don't have one nice thing to say. But then, by being quiet, I get judged for not being social enough. I feel like I'm in a situation where I just can't win. This has made my job so stressful.

This is mostly a vent. I just feel so isolated and powerless right now. I love my job but this part of it is torture.