As to the first part, I can't tell if it's sarcasm or not. I'm assuming it's not sarcasm, as I consider it to be a pretty serious dive. Throw in a DPV or a 'breather, or do it in a shallow cave, and then the equation changes. I know my max penetration in Mexico was MUCH higher as my max bottom time was 86 minutes, versus the typical 45 in Florida. As for the course, there were two of us in Cavern/Intro. Another buddy accompanied me through Apprentice. I was solo for Full Cave.
I agree with you on this, then. Your blanket statement was very out of line with my opinion, but this I agree with. I've told many people that they should be prepared to end the dive safely if the instructor has a sudden aneurysm. At no point in my courses did I feel like I was relying on the instructor. In fact, I'm more nervous when I'm with an instructor. I know I'm safe, but I know I'm not perfect yet....and while I'm always striving to get better, I'm just a little more aware of it in front of an instructor.