It amazes me sometimes how people are willing second guess the top people in the BJJ world. These rules are put in for a reason; to protect people from themselves, to protect competitors from aggressive individuals, protect the organization from lawsuits, and to protect the reputation of BJJ as martial art/sport that most people can learn and expect to suffer from a debilitating injury.
People get hurt by thinking they can hold out a little longer on this submission, or that only a wussy would tap out in competition. Knee injuries can take a long time to heal, I had a knee injury that bothered me for more than 10 years.
I've seen some very aggressive people in competitions who would not worry about seriously injuring somebody if it meant that they would win. Now at a black belt level I can see that if you don't tap out to lock then that is your problem but if you get hurt at a lower level you might never get to be a black belt.
Organizations have to very careful about what is acceptable and isn't. If someone was to be permanently disabled because the referee wasn't able to stop the fight in time for a number or reasons the referee, the opponent, the organization and the venue could all be sued. The lawsuit may or may not be successful but the threat of a lawsuit is enough for an organization to err on the side of caution.
If people get debilitating injuries from competing in BJJ or from training for those competitions BJJ will be seen by the public as being too dangerous for the average person to try.
BJJ for life, not just for a short time in your 20's.