I will disagree with this statement. The most easily snagged position for a QR skewer lever to be at is when is points away from the stays/blades. For a front wheel this means pointing forwards or down. For a rear wheel down or rearwards. Having the skewer lever run parallel or slightly crossing the stay/blade reduces the ability for something to snag the lever as the frame acts as a guard of sorts. Additionally if a rear QR lever is positioned running rearwards the rider behind you might not like having their ft wheel trapped between yoiur lever and rear wheel when you slow down faster than they do and they overlap wheel with you.

I generally position the lever to run parallel to the blade or stay, just off enough to easily grab with you hand but not hanging out like a hook looking for it's fish. Andy