Because wood splinters, and when it does, the chips move fast.
If you blink fast enough, your eyelid will probably shield your cornea, but it’s not fun.
It stops, but the hydraulics are still pressured up. Depending on what is the initial problem, it might start moving again at a moment you do not want it to.
As to wood-related injuries: my maternal granpdarents used to live in the backwaters of the Black Forest for 20 years or so. My background is in civil engineering and I have been in charge of building sites, and had all the training in H&S you need for that.
I have met my share of woodcutters, lumberjacks, forestry workers, sawmill operators, joiners, carpenters, builders of any trade… with scars, bits missing and interesting stories.
Never anything serious on my watch, though.
Conversation piece trivia: one of the first persons to make serious inroads in workplace safety, especially involving working with wood, was Franz Kafka. Yes, that Franz Kafka.
What you’re describing seems (and somewhat intentionally/willfully so) different from what was just described to you. A safety switch on hydraulics which does what you say there is a different kind of switch, and not a safety switch. As such it’s not much of a counterpoint you’ve made there.
One of the jobs my grandfather did after running away as a teen was working in a sawmill. He lost half a finger. He used this to great advantage on the grandkids playing the “you stole my finger” game.
Meh, I’ve been operating these log splitters for 20 years and I’ve never seen a fast moving splinter. Maybe if you’re stupid and put the log in sideways.
Safety buttons on hydraulic machines don’t depressure the hydraulics, they just turn of the electricity, which is what the lever does. Ok, it might be useful in case your suspenders get caught in the lever. Still not really an argument in this video, as there’s nothing in it suggesting the child doesn’t know where it is.