It's clear that a lot of thought went into that table. A dagger or club might be advantageous against completely unarmored opponents because you can change the trajectory of your swing almost as quickly as your opponent can dodge; but if your target even has light armor they can soak the blow on most of their body, and the advantage disappears.
It's kind of like how the DMG goes at lengths to explain how initiative is not a simple d6 roll either--longer weapons logically go first, but only when opponents close for combat; faster weapons logically get more blows in (but not always, that would be imbalanced, so only on a tied d6); any number of other factors might intervene.
Gygax was trying really hard to make a coherent set of simulationist combat rules, but the irony is that damage itself was completely abstracted into hit points!
I don't think that much thought actually went into the table, as Gary himself ignored the weapon v armor chart, psionics, space required for weapons, etc., which he talked about in his ENworld Q&A back in 2003.
Here is a very interesting look at that table, tracing it back to Chainmail, and that it wasn't originally a modifier chart, but a 'final target number' for attacks in Chainmail based on the Fighting Man. It was pretty much straight rolled over to 1e, without much adjustment. Here is a blog post (not mine) about it that I found fascinating, if the conclusions are true
The Big Mistake in Weapon vs. Armor Adjustments
There was a lot of complexity baked into 1e for various reasons, and Gary ignored a lot of it for his home games, and left it up to DMs to include what they wanted to make the game how they wanted - which I appreciated! 1e was my favorite edition, the PHB, and DMG in particular, offering so much random content, and charts, and options, and ideas. I still mine it today, and adapt it into my games.
I'm running OSE Advanced, and pulling 1e stuff in to flesh things out where necessary.