You know, in analysing this whole situation, from the start to now, remind me of a very similar situation in medicine.
Take the example of a face lift and a nose job. You can go through 5 to 7 years of residency as a plastic surgeon and get qualified to do it. Then come along the ENT docs, opthalmologist, dermatologists, dental oral surgeons - who started doing them with minimal (compared to a plastic surgeon) training.... And all heck broke lose. Standard not high enough etc, etc.. There is alot of truth on both side of the argument, but the end result is more competition, and lower prices (and lots of bad face lifts and nose jobs!!)... But the bottom line is, if you are dedicated enough, a simple procedure like those I described could be mastered by anyone...
In the same sense, it would be awfully nice to have the extensive training as suggested by Walter and Thallasamia. However, setting the bar that high upfront will reduce the number of rec diver by at least 90%, and increase the start out cost by at least $500 (meager compared to the expense in the sport). Simply, most people do not want to spend that much time..
These so called one weekend course, and even online courses, allow much more folks to participate. They certainly have their weaknesses. And certainly folks must take alot more classes to build up their skill. And that's where the additional "courses" come in.
I think it is good to focus on safety. And the lack of safety in these cert courses. But I get a little pertubed when one assume that all instructors of any one organization are simply incompetent based on what you see or heard on this thread is a little excessive.
Certainly, I do not back someone from getting a facelift from a dermatologist if it can be done by a plastic surgeon.... But it is not a technically difficult procedure, and I am certain, many other doctors are doing a fine job with it, without being a plastic surgeon.
I think ignoring all the argument about too many divers and damages to the environment .... A diver should not be discouraged from taking more classes (if he can afford it).... It is certainly nicer to taking a more comprehensive OW course (if one is close by), and experience and reading makes a big difference.
Life has sooo much to enjoy, and not worry about what credential you have... As long as you don't step on those coral polyps!