If the user cannot be trusted to make reasonable choices because he doesn't understand or want to read security popups, you have to make the choice for them. That's what Apple is doing and so is Microsoft. It's the only way to go if you want a secure system. And guess what: people appreciate a stable, secure system that makes it difficult to distribute malware. They appreciate it more than fear-mongering about theoretical issues.
Apple is never going to completely lock down the Mac because it can't be a development platform if it is locked down. Besides, why would they even want to?
> If the user cannot be trusted to make reasonable choices because he doesn't understand or want to read security popups, you have to make the choice for them.
I would bring up a libertarian argument to counter this view, but unfortunately I don't politically lean that way do it wouldn't be authentic. Somebody definitely should make that point, though.
Apple is never going to completely lock down the Mac because it can't be a development platform if it is locked down. Besides, why would they even want to?