They have changed the qualification structure for some sports, especially where an inept athlete could get seriously injured. After Eddie, ski jumping changed to prevent someone from qualifying who couldn't actually jump.
Rowing is reasonably safe. Sure, you could fall out of the boat but there is always a chase boat that can pull you out of the drink. The whitewater slalom events? Probably have a higher qualification standard because of the higher risk involved.
Something like gymnastics, the less adept athlete can just do easier routines; judo, they are beaten more easily. So there is less need for a higher qualification standard.