Trained karate for 7 years, Wado Ryu and Goju Ryu. Plenty of other techniques in karate...thats not my point
So why do you have such a problem understanding basic principles like human kinetics, and the concept that due to the longer line etc, (one of the reason sais are used in karate for advanced students is to extend the line even futher) a good full reverse punch will produce better short ones? And... what is your point?
not quite as practical when you have to take into account attacks below the waist.
Its not practical if you dont use your legs to defend you lower door.
As a former student you must know legs are also used defensively. As I said, boxers don't need to guard that area at all, therefore it makes perfect sense for them to use both arms to guard upper body and head. When your whole body is a target area, it makes sense to practice using lower arm blocks as well as upper ones. One advantage of blocking a low kick with your arm is you can grab the leg. Both arms can defend the upper area effectively from a free fighting stance, if required. The kids in that first photo of wtf?'s are in positions used rarely outside of kata and grading patterns in my experience.
I'm not debating the fact there are a lot of crappy karateka out there who don't even understand the basic principles behind what they're doing, I'm defending the value of certain principles when taught correctly.
(If this goes on much longer I'm off back to debating the existence of god.)