I had not seen this until today:
Quoting the owner, who is a friend:
What's amazing is that a push by a human arm can generate 20,000# force. Applied at the knife-edge of the wedge, that's some serious PSI. There are two pistons. The far one, operated with the left hand, is about twice ...the diamter of the near one. So it drives the main ram 4x as fast, but not as much force. For the hard work, only the right-hand pump is used, steadying yourself with your left hand on the far handle (operator standing at butt end of tool).
It sure is a lot safer than using a splitting maul. Less frustrating, too. You know the joy of having a splitting maul get jammed deep into a stubborn log.
...the manual/hydraulic splitter is a nifty tool. Human-power, bro! No fossil fuels consumed in the operation thereof. And I'm less likely to lose a toe or an eye!
Seems to be "correct tech" to me.