I got called a transphobe today and I gave a response that left the person without anything to say.

I was having a conversation with someone where I said that trans people deserve equal rights and that gender dysphoria is a difficult thing to suffer from and they don't deserve to be ridiculed. I added that I don't believe that someone is now the gender they transition to. They called me a transphobe and said "who are you to deny how they identify?" I said "how am I a transphobe when I don't identify as one?" She was standing there for a few seconds and gave the excuse of "that's not how it works".