I mean my personal take on it is that if you don't have a most basic understanding of control theory, you won't understand what your monitoring system is telling you nor will you know how to programmatically react to it.
In fact, I have a perfect counter example. At reddit, to even out load on our databases, we built a system that would take into account current load on the database when choosing which read slave to select. As it turns out, this doesn't work well, because you overwhelm the slave with the lowest load because the the reaction time is too slow compared to the request time. We had to tweak it to account for this.
Had we known control theory, we would not have made this mistake. On the other hand, that mistake didn't cause us that much damage and we were able to devise a solution that ended up being right. :)