I've used my bike rack in the hitch before with nothing in the bed.
I don't have any other way to carry them without throwing them in the bed and letting them get thrown around. Not about to do that with a $1000 bike (more with friends' bikes), especially when I have paid $200 for a nice hitch rack. I got the hitch rack back when I had a Ranger, which didn't have room for 4 bikes.
Don't be so quick to judge.