Why cant we sell health potions on the AH like dyes and other commodities?

You get them from drops just like any other item so why can't we list them on the AH? What makes even less sense is dyes don't drop and are only vendor purchased items yet they can be sold in the AH.

I always find myself in a mass excess of HP pots because I always loot them to avoid buying them. They only vendor for like 20g but cost something like 400 at the vendor... so being able to sell them on the AH for like 200 each would allow me to offload my extras to make more while allowing people to buy them cheaper and save money.