There are no ethical choices under first-past-the-post voting. We must instead make a decision that reduces the most harm.
I recommend a descriptive approach to definitions as opposed to a prescriptive approach. I think that would resolve a lot of the discourse we are having. I have explained what I mean in my argument. Your argument centers on this false idea that definitions can limit what a person thinks and believes. But definitions are only as useful as they help us communicate.