His point is somewhat valid, though, in the sense that there are variables that work together that impact the final flavor of the beer. One of the easiest to control is pitch rate, but other things like nutrient availability and dissolved oxygen also play a role. If you pitch low, but have an abundance of nutrients and oxygen in your wort, you are far less likely to have off flavors than someone pitching low with poor levels of available nutrients. By controlling the controllables, we minimize the risk of creating off flavors due to uncontrolled variables. Given that most people start out paying very little attention to nutrients, pitch rate is the easiest variable to control to produce consistent results - increase pitch rate to minimize potential off-flavors due to varying levels of nutrients. If pitch rate was the only thing to be concerned with, Gordon Strong would probably not be making very good lagers. If you have the ability to control a flavor-impacting variable, the responsible thing to do is to control it. If you understand how other variables are interdependent, and you can control all of them to a degree that produces consistently desirable results, more power to you, but that isn't how most people start off in this hobby - hence, the typical focus on healthy pitch rate via a starter.