Madcow is right, in specific strength-related endeavors there is more of a 'standard'. Olympic lifters tend to lift in the purest form in my opinion, over the years and due to the inreased use of equipment, powerlifting has evolved a lot, but still, there are standards that would be considered good, fair, and poor form all across. The only differences are individual leverage and proportion issues and personal strengths and weaknesses like pulling conventional or sumo, squat or split snatching, split or power jerking, etc.....
With bodybuilding, there has been all sorts of different things done over the years, and with no performance criteria, things have gotten blurred. Throw in widespread and increased use of anabolics to enhance the shittiest of stimuli and you get utter garbage like the Weider Principles, Gym Lore, and Pseudo Science. Add in the fact that people who do not have performance criteria will try to dance around heavy squats, pulls, and to a lesser degree presses and avoid olympic lifting like the plague, and you get the reason most Bodybuilders train the way they do.
Now, Bodybuilding publications are readily available in news stands, while things like MILO are not. The recreational lifter will follow what is readily available and will assume since strength is not his primary goal, that that other stuff is not needed and is just specific to competitive strength athletes. When the crap they read about and then do in the gym doesn't work, they assume that they are maxed out on their potential and that the only way to growth is through steroids or supplements. IF steroids are not accessible, people tend to buy whatever supplement is being heavily advertised. The supplement companies (many of which were founded on money made from steroid sales) pay millions and millions a year to run ads in magazines because that is where all their business comes from. And just in time for people to realize something didn't work, something new and better PROMISING results comes out, and because they can't just say 'squat, pull, press, that simple' and continue to keep selling mags, the magazines keep churning out ridiculous, assinine training info, and in conjuction with the supplement companies they create the lie that has become bodybuilding and recreational lifting. This lie is that training alone and getting good at compound lifts won't yield results, but there IS a magic combination of sets/reps/exercises/supersets/foods/drugs/supplements/cadences/tempos/angles/arcs/planes of motion, and once you find it by reading the mags for the LATEST discovery, you will magically be on the road to growth. The proof is in the pics. Guys like pro bodybuilders, juiced to the gills, who are huge because they are on enough gear to make signing your name cause enough stimulus for forearm growth are in in the pics so this MUST mean this info is legit.
Anyway, thats what happens, and thats why although there are 'standards' in EVERY other sport, bodybuilding and recreational lifting (because it is tied to bodybuilding) remains one of the most frustrating and mysterious pursuits for many. This, along with there being no interest in performance, and the fact that drugs can enhance shitty stimuli, are why so many people do so many bone-headed things in the gym. People will see some dumbass with 36'' thighs doing little sissy quarter squats that resemble more of a courtsey than an actual squat (The Markus Ruhl video comes to mind) and think this guy is HUGE, maybe for bodybuilding purposes you don't need to do full squats.....so people pass this info on to their friend who passes it on to his dad who passes it on to the guy at work looking to 'tone up' and you get a bunch of people with misinformation, where if the guy who saw the Ruhl video rationalized that Rhul has freaky drug receptors and an ability to tolerate massive amounts of gear, thus allowing him to look the way he does while training like a turd sandwich, then the misinformation wouldn't have been spread by him, possibly allowing everyone he talked to who believed him to to actually make progress in the gym.