That's an argument for unmoderated flamewar. That's not what HN is. If you're imagining a version of HN that is "like the current HN, but without the current moderation practices," you'll have to forgive me for considering that a fantasy.
There's also no evidence that anybody said that as a "discussion sinking" tactic. On the contrary, the simplest explanation easily applies: people responded to flamebait with more flamebait, which cascaded into flamewar. This is one of the most common phenomena that exists here, and one doesn't need sinister constructs to understand it.
And yes, it's a perfect tactic to sink any topic on a site with any kind of automoderation.
You cannot properly discuss anything moderately controversial if any topic can get framed, and sunk as "flamebait" because moderately controversial topics are "flamebait".
People have heated discussions about matters of ideology, that's the very obvious truth of life.
The more important is the matter, the more, longer, louder, and more emotionally people will argue.