That's the thing. For some people supporting 45 is legitimately a personal betrayal.
On the whole, I agree with what you're saying. It just doesn't apply to Trump and Trump supporters. It's the lies and the bad faith with the American people. Any real friendship has to be based on a shared history, a common truth, and good faith. If you support someone who brashly abuses those basic tenets and that's okay with you, then a friend would be wise to question how much of a friend you can really be if you don't understand or have any respect for the basic building blocks of friendship. And to ask, "are they gonna throw me under the bus at some point?"