I love when someone starts a conversation with me, assuming I agree with their stance. As a personal policy I don't talk about religion or politics at work.
Today they stuck me with the new apprentice. After working with him for an hour, he starts talking about how great Trump is doing. I stood there quietly and allowed him to talk. Soon I realized that he is taking my silence as agreement. I hope that people don't look at me and automatically assume that I'm a Trump supporter!
I share you position! But I have no problem talking about either politics or religion at my office since I am a writer and the only person in my studio except for Henry my Golden Retriever cat (he thinks he is a dog) and my lab/pitbull mix, Cody who KNOWS he is a dog! They never object to either my politics or my spiritual beliefs.
One technique that works quickly is to totally ignore and don't even look at someone who is behaving in an offensive manner.
If you can, just leave the area whenever the person starts talking about an unwanted subject. Only smile at and respond to them when they are being neutral and friendly.
This behaviorist technique gets rapid results.
You are in the Libertarian group are you not? I wouldn't want to work with someone who brings up either politics or religion or personal life issues.
I am in the Libertarian group.
This same kid told me about his "weird dreams" in our first ever conversation, 2 minutes after meeting him. I don't even want to hear about my girlfriend's dreams.