Why are un-baffled tanks typically the ones chosen for hauling food products such as milk?

49 CFR 383.119(c); AAMVA CDL Manual Section 8.2.5, "Un-baffled Tanks," p.8-8-2

This explains a fact that otherwise seems backwards: the tank design that handles worst (strongest surge) is the one required for sanitary food hauling. Understanding the sanitation reason behind the tradeoff helps a driver connect cargo type to expected handling before ever getting behind the wheel.