I think the ambiguity is kind of the point. If things were written out ("doing X is monopolistic"), then it would be easy for companies to operate in an noncomp

I think the ambiguity is kind of the point. If things were written out ("doing X is monopolistic"), then it would be easy for companies to operate in an noncompetitive manner, so long as they don't violate specific laws. Plus, the definitions of things like monopolies vary so much across industries, that it would be impossible to come up with specifics that cover every instance of anti-trust violations. I don't think it's perfect, but I do think it's more effective than the alternatives.