Apple owns CUPS, having bought it a few years back.
AFAIK, CUPS is open source. Dunno what you are thinking of.
From the CUPS web interface:
CUPS and the CUPS logo are trademarks of Apple Inc. CUPS is copyright 2007-2011 Apple Inc. All rights reserved.
Apple dipshits. It's still open source.
Open Source and Copyright happily co-exist. You retain your copyright even if you release something under a GPL-type licence, and you have the same rights to sell or transfer that copyright, which is what happened with CUPS. It doesn't put a restriction on usage beyond those stipulated in the licence, and the original owner's moral and Lockean rights remain unabridged. No evil involved. It's common.
I can't say I've felt a strong urge to print from an iPad, but I'd imagine a full CUPS implementation would add bulk to iOS, whereas AirPrint transfers the onus to the manufacturers and their hardware, and iOS only has to support the single lightweight protocol.
As Jaded says, a message is something else. Tap an email address (anywhere in iOS) and it'll open a new email draft in the mail app.
Again, not particularly evil.