I think this exchange from the article sums it up pretty clearly:
MM: Bush had no business saying we won. This is another Vietnam.
YM: We could have won in Vietnam, but the will of the people wasnt there (a view supported by historian Mark Moyar in Triumph Forsaken).
MM: Yes, its another quagmire like Vietnam.
The middle aged man didn't want to hear what the cadet was saying, so he ignored it and just kept talking. Life in reality can be a challenge for some folks.
The middle aged dude was an rude ahole. I see your point.