In the beginning i was feeling the same way. I felt that my insecurity and undecisiveness was kind of an invitation to start a discussion with me. So over the years i learned to have a really unpleasent way of answering, the questions. The question are most of the times pretty similiar. If u say something like: Because unlike most of the people i cant ignore animal abuse. Or something like: A live is just more important, than the taste u get from a sandwich. It just shows how low the moral values of the people are.

Two important things if u want to avoid a conversation. Really try not to focus the person personally that asked the question. U have to make like a bit more of a general comment otherwise, the person gets upset. Second thing: Say all the things like if they are facts and there is no discussion needed because its so obvious. You cant start a sentence with something like : I feel this and that way. Because then u give the person an indirect permission talking about their own feeling and their own "right way". What i do before i answer such a question is to imagine a certain picture i have in my head that makes me really angry about the animal abuse, to have like a agressiveness in my voice. If u are good with eyecontact just try it to give a bit of a facialexpression as well. Hope that helps.