For most, MOST crossfitters, they cannot achieve good technique without private lessons or professional coaching. There are those however, who take is upon themselves to become good lifters. They are meticulous in their training, film everything, watch/read every article and clip on the internet on lifting and then they spend hundreds of hours perfecting their technique. These are the athletes who become good coaches, because they have been through the process and can articulate how the lift should feel. These athletes are usually successful in achieving good technique (relative to professional weightlifters). There are others (ie most professional/amateur crossfitters) that get away with subpar technique because they are A: strong B: they rarely have to move loads that require better than okay technique. This was true up until the more recent workouts. Take Open Workout 12.2 for example. Rich Froning squared off against Dan Bailey in a head to head snatch battle. Both of these athletes are by far and away better than most crossfitters in the world, but what the workout came down to was technique. Rich was more technically proficient than Dan and it was enough to best him by a few reps. A quick look at Bailey's technique will show that he never gets the bar back into his hips, he initiates extension way too early, and pulls bar up with his arms; and this is a guy who finshed top 5 in the world at the 2011 Crossfit Games! On the other hand, every snatch that Rich pulled looked the same from 75lbs. all the way up to 210lbs.. He looked like he could have done it all day. When you combine very good technique with THE BEST engine in the game, you get a dominating performance that no one else in the world could best.
Ranting aside, I can see why the olympic lifting community wants to vomit every time they see a crossfitter "PR." It's usually some kind of early pull/weird bar bath/miraculous that they are alive moments. Whereas when professional lifters PR, it looks like one of their warm-up snatches (in terms of sequence, speed of pull, etc.). See here: