Apple has proprietary, in-house solutions for these tasks. If I were an employee working on one of those, I wouldn't like if a different part of the company provided support to or funding for an alternative to the thing I'm working on.
https://developer.apple.com/library/archive/documentation/Ne...
But it's a big company, so presumably some team used curl for some project, leaked that in an error message, and whoever runs the Apple Support social media account apparently didn't know about that after someone contacted them about the error message. Or something like that, it's hard to figure out what was going on without more context.