I didn’t realize it was other wise. Under 25 your brain hasn’t fully developed and you can’t be trusted to rent a car, but you can take a strangers life in your hands.
I also rented cars multiple times as a 21-year-old in the US and without paying a risk surcharge as well.
The process you need to go through to get a pilot's license -- especially a commercial one -- is pretty rigorous and I would have confidence that anyone, of any age, who does it is qualified.
The process you need to go through to get a driver's license is very far from rigorous, and I don't assume that just because someone has one, at any age, that means they're good at it. So the statistics are more relevant. There's a very good reason why car insurance premiums are higher for people under 25.
It’s also unfortunate to see a large group of people dismissed based on a single statistic, when in reality brain development is a much more complex process.
They literally have an always on track of your location with them while you are driving for them, it wouldn't be too much to hook that into a OBDII interface to monitor safe driving.