I read that double handed punch was popular in film back then because they needed big, dynamic attacks, that looked powerful, but they didn't have the fight choreography knowledge yet to use actual fighting moves. This move looks impactful, but doesn't actually do much damage, so they can go full force without concern of putting a star actor on disability.
Yes, ‘blank-Fu’ has been used since the 70s, but as a long time fan of both Trek and HK action films, I can’t say that what Shatner was doing in TOS was referred to in that way until recently.
Is it really so controversial to say 1) Kirk Fu became current in the fandom since the book was published; & 2) the meme is a clear lift from a published work and the drawings its artist Christian Cornia, they deserve credit?
It looks a lot like stage fighting. Something that would still be clear to viewers sitting really far away (or I guess with tiny, blurry 1960s TVs in this case).
It's basically that. These have a lot in common with pro-wrestling moves. They all carry some element of risk (like the drop kick), but the physicality isn't impossible to achieve with some coaching.