So, how did you feel when you read that bit of sf hand-waving?

It makes me go like this: ಠ_ಠ

Aside from that, when the person making the bad argument is someone I can empathize with, it often makes me feel embarrassed on their behalf; like, if it's someone I identify with enough that I can generally imagine myself in their position, I often imagine myself making the bad argument, and, being that I-as-myself can see why the argument is bad, I immediately feel embarrassed, including the associated physical sensations.

That's the same reason why I don't like movies about awkward people.