Kirk is.
Here's one of the things about western combat sports (and combat sports in general, this can apply equally to kendo) is that they tend to test a very limited skillset. Foil fencing is much simpler than longsword or messer fencing, and modern boxing has a very restrictive ruleset compared to pre-MQB rules. Somewhere along the line competition became more important than a more serious application of MA. It was considered more important that someone could score a "touch" with a foil than skewer someone with a smallsword while disarming him or taking him down with a trip. It also became more important that someone get a pin in wrestling than break the opponent's arm. It became more important that boxing matches be settled with big gloves and only punches than bare knuckles and takedowns.
Perhaps the sportification of an art necessitates a reduction in the amount of techniques? Even in tournament HEMA, there are banned technques, and rightfully so. We want people to survive tourneys.
However this doesn't explain why in Asia (and toa elsser extent other countries where boxing and collegiate wrestline iis not the dominant combat sport such as Brazil, parts of Africa, Russia, etc) despite the dumbing down of popular local styles to remove dangerous techniques, they still left in kicks, leg locks, and other movements utilizing the legs.
I mean I cannot understand who the hell thought "kicking" was a sissy's technique thus removing it from boxing.
Well in fact when kicking was re-introduced in mainstream Western fighting sports (as seen in the explosion of kickboxing when it was initially introduced in the West, the still remaining popularity of Asian sportified MAs, and MMA) one of the novelty of how so many young people were eager to take Asian MAs was the use of legs and other bodily parts.
I mean BJJ is now quickly reaching Collegiate wrestling's popularity (and its only the lack of university sposorship that prevents it from overtaking restricted forms of wrestling popular in the mainstream West). And a big part of this is attributed to the use of legs and elbows to pin an enemy instead or relying almost entirely on hands.
I mean there was even a point Savate was raging in popularity in Europe and far surpassed boxing in its home country.
But boxing and other fighting sports only using hands or arms (not counting use of elbow to hit or pin an opponent) overtook Savate and its not until post-1970s that kickboxing came out in the west as somewhat mainsream (but still paless in comparison to boxing even during the initial explosion).
I mean using the restriction explanation you put above, how come Asia and the rest of the world never had a form of sport restricting to just using your hands (or more specifically fists)? How come its only in the west where s sport that only allows punching exploded in popularity? I mean I have yet to see a historical evidence for "MQ" or even "London Prize" style sports existing in Asia before Westerners brought over their now sportified form of pugilism in the late 19th and early 20th century.
Even styles that rely primarily on hands utilize some kicks or sweeps every now and than in combos and their handstrikes include hammerfist, open palm strike, spear thrust and backfist rather than just pure punching.
The same can be asked about the development of sport wrestling in the West. Even Mongolian wrestling, the closes equivalent I can think of in Asia, allows sweeps and Judo style throws (as long as only arms are used) despite the fact the sports emphasize arm style wrestling to the point of even looking exactly as collegiate wrestling the overwhelming majority of the time.
If the closest equivalent in Asia still allows leg movements, it makes me wonder what the hell were Western promorters thinking when they sportified wrestling and boxing!