Your tablesaw example doesn't really disprove anything, that's why they now have riving knives[1], push sticks and lifting guards that make them a heck of a lot safer.
It's not that they can't be made perfectly safe, but that you take reasonable safety measures and mitigate risks appropriately. If he had this off in a shed ~40ft from the house that's a lot different than inside the garage.
The article didn't mention how he's connecting it to the grid so there's a very real possibility that he could have an inverter directly connected which is why we have building codes and inspections to catch things that have the possibility to kill people or do significant property damage.