There is another dimension here. You are assuming hand coded bots are fitter because they have working genes to fight, find food, etc. that mutated versions don't have but it doesn't matter how good you are at doing something, if you can't survive/reproduce in the real world - a real world that includes random mutations - you are unfit by definition.
Hand coded bots are very very very unfit with respect to their genome's ability to withstand mutations and mutations are a big part of their environement in an evo sim. Human created software of any kind is incredibly fragile. One bit gets changed and the thing is a piece of toast. Of course complex hand coded bots will exhibit loss of macro behavioural functionality when subjected to mutations! Of course! All mutations are bad for them! They are sitting on top of a very very steep, local peak in the fitness landscape, one that in all probablity is not even reachable via evolution because all the slopes are too steep. There is no path of incremental changes leading from one sucessfull organism to another that would result in that genome. Their genome did not evolve and hence is not designed to suffer mutations well. Humans don't code that way. When you mutate them, they fall off the peak, generally a very very long way.
This is why in my opinion, starting an evo sim with a complex hand-coded bot is little better than starting one with random garage. You have to come down off the peak onto some path where evolution can work with you and take you somewhere.