So you defined your own idiosyncratic version of "moving the goalposts" and used it to rebut his argument, with a condescending "you understand that's how science works, right?"--instead of being honest that it is you who are changing the definition, and not his failure to understand anything.

I don't see how that's any better.

He rebutted the argument about moving the goalposts by moving the goalposts. It’s better by dint of sheer bravado.