I don't understand how it happens. Not enough even happens for it to be so bad it is good either. You watch it for five minutes and it is funny and then you feel sad. Sad that somewhere in there is a list of credits thanking people for their hardwork.
I wouldn't necessarily blame the developers - there were probably a bunch of people actually doing the work who were screaming "you can't release this yet, it's not finished" - these decisions generally come from further up the tree. Been there, and I know how it feels to see something that isn't finished being delivered against your advice. It is not a nice feeling.