Dunno bout Defendo and all that, but Krav Maga was made by Imi Lichtenfield for those fighting for a country before Israel was formed. It is made from scratch solely to provide a good system that was fast to learn for soldiers. They didn't have much time for training as you might understand. Imi previously trained wrestling, boxing and such arts, but never had anything to do with JKD. In fact, the roots of KM are somewhat older than those of JKD. Krav Maga was later developed further after Israel was formed and now even has a curriculum available for civilians which is pretty popular in Israel. The army, police and special units also still use it and those responsible for KM (notably Eyal Yanilov) still work on developing it, so that it meets today's self defence needs. If a new type of attack is statistically being used a lot, Krav Maga will add a defence for it to the beginner curriculum - KM works closely with police and the army to figure out what is necessary to add.
A very good side of KM is that a beginner can become effective in a very short period of time. Krav Maga teaches all its instructors proper ways to teach the art based on modern research in teaching methods. Just like every high school teacher is taught how to make the students understand concepts, every KM instructor is taught how to explain why techniques are used and set up the way they are. After some intensive training, the student will be proficient in fighting another less technical fighter. Of course, if you want to fight other pro-fighters, you must spend a lot more time training, but most people need to learn how to survive attacks from others that are not pro-fighters. A rapist has probably not been training BJJ, Muay thai and JKD all his life. Tactics to avoid fights and attacks, using common objects for defence and drills to get the right mental attitude are also included in the system. It is pretty dirty fighting, I agree, but it's what you need to know and there's a LOT more to it than just learning to bite. The thing is that most people can't make themselves fight fiercely, ie. gauging at eyes, biting the throat and kicking to the groin. It's simply something the average civilized person does not want to do. So a lot of training is for developing more of an instinct for fighting and developing a mental state where you don't care for the opponent. The Krav Maga student learns to consider his assailant as an object, something that must be destroyed for one's own survival. It's rather cruel and insensitive, but it's what you need to survive someone who wants you dead.
Personally I like the system a lot
And remember: Just because you practice JKD and think it's a really good system, does not mean that every other good and effective system is a ripoff from JKD. It is possible for other people than Bruce to come up with good ways to defend oneself.
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