I get frustrated that I can't play with a lot of cool moves. I really love the bicep crusher from spiderweb, and can not use it, for example. But to be honest, the guys in my gym will let me attempt all of them except the heelhook if I let them know in advance that I may, and I understand why every single one is illegal. Just to play devil's advocate (because I actually do wish some of this was allowed), here are some counter points:
Toeholds, leglocks, and kneebars target the knee. The reasons the knee is different from the arm are strength, flexibility, and sensitivity. Your knee is way stronger, so it can take way more pressure. So by the time the guy gets a lock tight on your knee, he is pulling his ass off, with less control than an armbar by far. Your elbow is more flexible, allowing more distance between the feeling of pain and the snap, and more sensitive, allowing more time between the same. Also, recovery for a knee takes much longer, the injury is far more debilitating, and way more likely to leave permanent lasting pain and immobility.
The bicep/calf crushes are the most annoying for me, but I understand. I have seen from both ends how easy it is to literally crush a bicep into tearing, or snap the arm with that move. It just tightens up so quickly, and often doesn't hurt all that bad right up until the injury. Also many of the same problems with knees vs elbows apply to calfs vs biceps. Plus many calf crushers come very close to, or do attack the knee at the same time. I think we could let these rules go, but at the same time I don't want some over-excited blue belt who just learned the move to take me out of competition for a year.
Slam from Guard is obvious, and cervical locks are understandable (a broken neck wouldn't go over too well).
What the hell is their definition of scissor takedown again? Because I know that doesn't mean a scissor sweep.
One other point about a comment above: You can not do a neck crank, even from triangle. People get away with it in triangles, head/arms, guillotines and rncs because you can't tell if it's a choke or a crank, and you can defend the choke by turning into the crank instead. But you are not supposed to crank the neck in the gi, period, and doing so is without a doubt dirty unless your opponent agrees beforehand. I like to train with it nogi, but I don't want to go home every single day unable to turn my neck to the side, so I train without it in the gi.