Maybe the Satoshi of November 2008 is not the same person as the satoshi here...
"Don't use this patch, it'll make you incompatible with the network, to your own detriment."
It would be meaningless. Clearly, Satoshi is dead afraid that his bomb would be removed. Of course this is bullshit because jgarzik would, in practice, never mine a block above 1 MB. So he wouldn't be "to his own detriment", be "incompatible with the network" most of the time.
The impression I got from that little exchange is that Satoshi thought Jeff didn't realise he'd be forking himself off the network unless everyone else used the patch as well and thought it would be a good idea to point that out. It was probably a fairly sensible idea to avoid a situation where half the network would obliviously run the patch and half didn't run it, thereby splitting the network and making a complete mess.
That's obviously not the case, as I tried to point out. First of all, Satoshi couldn't know what would be the fraction of the network that would apply the patch. So by applying the patch, Jeff might just as well get the majority behind him, and it would be to the detriment, not of Jeff, but of those that didn't apply the patch.
The fact that Satoshi assumes that Jeff would automatically be in minority - or at least, wants Jeff to be afraid to be in the minority - is telling.But secondly, assuming that Jeff himself wouldn't mine, himself, a lot of big blocks (one can hardly think of Jeff wanting to spam the network himself), and assuming that the rest of the network WOULD filter out the big blocks, and only make a small block chain,
Jeff wouldn't, at all, "make himself incompatible with the network". Jeff would accept ALL the small blocks made by the network. Most probably, Jeff would mine, himself, also only small blocks and get them accepted by the others. The only difference between Jeff's code and the rest of the network, under the assumption that they don't follow Jeff's patch, is that Jeff's node is more permissive. So he won't be incompatible with the network.
Satoshi is telling bullshit here. And I can't imagine that he doesn't know.
At no point, his phrase, that it would be "detrimental to Jeff", is true. It would ONLY be true in those rare circumstances that Jeff wants to mine a big spam block, and the majority of the network doesn't follow him.
And it would only be detrimental for Jeff's PoW on that sole block. Jeff's node would accept the fact that his block was orphaned, and that another chain with smaller blocks took over. From then onward, Jeff wouldn't be "incompatible with the network" any more.
So this is simply utterly wrong.
The only "dangerous" situation is when Jeff is in majority ! When Jeff-like majority miner nodes mine a chain with big blocks, and the minority Satoshi-like nodes don't accept this, and mine their own prong - or adapt. At no point, anything is "detrimental to Jeff".
Again, the "narrative" of keeping blocks small
wasn't Satoshi's. Satoshi merely went along with the idea after hearing what must have been some pretty convincing arguments. In many ways, it's a shame we'll never get to see all the communications exchanged between Satoshi and Hal Finney, given their historical significance and the tremendous impact those conversations had on how this has all unfolded over time. It's also likely Satoshi didn't envision themselves withdrawing from the community when they did, effectively exiling themselves and going into hiding. There's no way they could foresee the WikiLeaks donations thing in advance, which was clearly a catalyst in prompting Satoshi's decision to leave. So it's entirely possible Satoshi did have plans to alter it later, when it became the contentious issue it eventually did. When Satoshi left, blocks were still nowhere near their full capacity, so it could well have been something "on the back burner". But sadly we'll probably never know for sure.
I certainly don't get the impression it was anything malicious on Satoshi's part, though. That's a bit of a stretch.
I have a hard time imagining that Satoshi didn't understand what he was saying, but nevertheless said it. I have a hard time thinking that Satoshi:
1) didn't understand the arguments of the danger in the long term of locking in the 1MB limit
2) didn't understand that not applying this limit didn't exclude you from the network at all
3) was capable of suggesting how it could be done safely with an if (blocknumber < ...) {limit} but didn't do so
4) but nevertheless said that it was dangerous to remove his constant as it would exclude you !
except of course if Satoshi was just a sock puppet of Hal Finney and didn't understand zilch himself of this stuff.
It simply doesn't fit together.