The gist of what rubs me the wrong way is that Apple is following curl’s license precisely and people are still unhappy.
I view Apple's behavior the same as I do people who leave their shopping carts loose in the parking lot instead of returning them to the corrals. Sure, they aren't legally required to provide any form of support to curl, but they would anyway if they had any decency.
Sure, Apple ships curl, and maybe doesn’t support it (are you sure? Don’t they build and test it from source on their own servers? Isn’t that a form of support?).
But Apple also ships and supports WebKit, which - as the original basis for Chromium - has arguably had a bigger impact on the world than curl has. And I suspect that Apple also contributed to some of the standards that curl relies on. Of course, Apple built WebKit as a fork of KHTML… but if memory serves, they didn’t have to make the fork open source.
I’m not trying to defend Apple in any way, I just think that the conversation can be a bit more sophisticated than just “big company ships free software and gives nothing back”. Apple has shipped some really cool open source software in the past, and I think it’s disingenuous to suggest that they owe something to every package that they ship. That is not really in the spirit of free software.