and the load.

Tour bikes are built to carry the load. If you aren't carrying much, you can use a road bike (ultralight touring, credit card touring) but if you are carrying a heavy load (say >15-20 lbs) then the touring bike can carry it without sacrificing handling and having wheel problems.

Certainly if by touring you mean supported touring where you're not carrying stuff, use a road bike! I do supported tours on my road bike, credit card tours on my road bike with an ultralight rear rack and bags, and fully self-supported camping tours on my touring bike with 4 panniers and a handlebar bag.