I've been involved in this sort of anti-poaching discussion at senior levels before. It happens all the time, in many industries - particularly in jurisdictions non-competes are enforceable. When an executive leaves one place and goes to another (say a CIO or VP), they bring people with them. Often in violation of non-solicitation and non-compete agreements, which are a pain in the ass for everyone to enforce. So you do what you can to Stop. The. Practice.
In the case of California, Jobs didnt have a direct legal avenue to stop this so he wanted to use other threats to stop a competitor. That seems normal. If it was not legal, then his lawyers did him no favors. Immoral? Not at all. It's business.
The reaction here reminds me of Slashdot circa 98, clucking over leaked Microsoft memos. The hacker/open source idealism here seems way stronger than that of entrepreneurs or business people. Makes sense I guess.
Perhaps people love early stage companies here because they can ignore the dirtier parts of business after you have a product/market fit... like, competition.
Competition is dirty and messy. It's not a kid gloves "lets out innovate each other!" like you're toddlers in a sandbox not allowed to hit each other. It's about marketing negatively (see Samsung's anti Apple ads), aggressive sales and pricing (see the Nexus 7 sold at cost), stopping poaching (Apple above), and removing supply lines by buying them up (Apple with displays and flash memory).
Sure, business isn't JUST those things. It also is innovation. Preferably lots of it. But people here are a rather naive if they think most companies aren't spending over 50% of their time on the former. Apple is actually unique for their size in how much time it spends innovating rather than, to paraphrase Ray Kroc, "sticking a live hose in your competitor's mouth".