Unless I'm misreading something, both the text and graphic of that page seem to indicate it's 4.1km/s from low Mars orbit to the surface of Mars. I can't find anywhere saying it's 4.1 from LEO.
I get 2.5+0.7+0.6=3.8 to get into Mars Transfer from LEO. If we were to execute perfect aerobraking, the rest would be free. It for sure wouldn't be perfect so some fuel will be needed but not that much.
