Something about the tone of the messages rubs me entirely the wrong way.

It reads like justified opinions from experience. Not seeing much emotional tone in there.

Well on one hand you've got engineers at a billion dollar company explaining how they've solved a problem. On the other hand you've got some random commentor on HN over-simplifying a complex engineering solution.

Sounds to me like it's some "random commentor" who has solved a similar problem at a similar scale with a solution that's much simpler.

I dunno, sounds very ‘I am very smart’ to me. They may be right or they may not, but both solutions sound workable to me.

Don’t let perfect be the enemy of good, and all that. There’s enough utter garbage around to shit on.

I think you're reading into it. They are stating that the solution in the post was overengineered, and describing an alternate solution that doesn't require as much abstraction or resources, but is manageable for data with a much higher dimensional structure

The fact that you read that as "I am very smart" and that that was a reason to downvote the post, tells more about you than it does the person you're supposedly describing.