Point 2: Linux users have been getting phishing attacks for just as long as anyone else on the internet. The difference is that we're generally clued up enough to ignore them.

Point 3: I didn't see the email but I assume it was HTML email that contained a link to download the "fix". That link would not have been to the Red Hat web site which would have aroused my suspicion and I would have investigated further before clicking it.

Linux users don't claim to have some inherent immunity to phishing attacks like this, but generally they do come from a culture where you are far less likely to click on random links in email or install random pieces of software.