Why Something Rather Than Nothing?

[Heywood]

So, you are going to sit here and defend "if I define this dog to be god, then you believe in a god, and aren't an atheist!" as a sound and worthwhile argument to make?

Is that what's happening here?

Defining terms is valid, but so is the recognition that words have meanings, and that when you're defining terms you are selecting from a list of possible meanings, not applying whole new, never before used ones to words. Least of all when your goal is simply to invalidate what your opponent chooses to call themselves, and not argue against the meat of their position.

What is happening is you are criticizing his definitions rather than his argument. That's the cheap trick being played.