I'm not going to go one way or the other on this one, but to be fair, it's VERY important to remember that it's not the volume of security patches, but rather the severity of the of vulnerabilities.
You can't compare a vulnerability that takes a few unlikely scenarios and compare it to something that leaves your computer wide open.
EXAMPLE #1: The SSH vulnerability a while back. There was an update, but lets be honest with ourselves. Of the whole mac community, how many people even enabled SSH. I would have to say 1%... or maybe 2% on the high end.
I'm not saying that Apple shouldn't have fixed this immediately (which they did), but I think again, you are comparing apples to oranges.
EXAMPLE #2: The current DHCP vulnerability. This is an issue... that being said, the odds of someone having the kind of access that is required for that type of exploit is quasi-unrealistic. I'm not saying that this shouldn't be taken with the utmost seriousness.
Also, MANY of the OS X vulnerabilities have been Unix® wide problems, not just specific to OS X.