Youre arguing semantics

Is there a name for this argument?
Is there a name for this? A friend posted a question asking, basically, if we're going to have the rich pay their fair share, what is a fair share?

It seems to me that there is a name for this kind of "debate", wherein everyone knows there is no one right answer, yet the questioner gets to feel (morally? intellectually?) superior for having asked it. Or "proves" their point (that the current rate is just fine) by showing that no one can prove there is a different, correct answer.

I hate this kind of thing, and I want to call him out on it (don't worry, we're very old friends who like to debate with one another). But what do I call it? "Dude, you're being . ?" Specious seems close, but not quite right.

See also:

• se.video