Yeah, I don't think it matters that much. There are lots of random gotchas that you have to watch out for using the socket module.

To be clear: I do still think that using a large value by default, and clamping user input values at 65535, would be improvements. I just don't think they're important enough to spend energy arguing about it :-).

The reason I'm not worried about large backlogs wasting kernel memory is that servers all call accept as fast as they can. This means any incoming connection flood will end up taking memory regardless of the size of the kernel-side buffer. And I'm pretty sure the kernel buffer ia a linked list, so setting it to a large value doesn't cost anything if you're not using it.

Anyway asyncio at least should probably update its default.