Only some of them take care of it "for you" but it still requires knowledge and experience to know how to work paramaters correctly. Some software strategies are different than others. For example, Volumill uses a baseline stepover and nominal feedrate to calculate a constant chipload by varying the feedrate in the cut, whereas HSMWorks strives for a constant stepover at the nominal feedrate, although internal corners can be modified to suit tooling or preference.
The general principle is the same, but the methods vary. Being good at utilizing your tools takes time with the software and the machines you're running. Nothing is ever really done for you.