why are bots programmed to fail?

I could see an argument for having a certain chance to fail generator checks, but I don't think failing healing skill checks is needed for balance. Bots already can't make nuanced decisions or respond very well to more complex teammate signals. I've seen them spend the rest of the match in a corner of the map. Why deliberately make them fail healing skill checks, double-screwing teammates over for the ragequit? It's not as if the skill checks can't be cordoned off into different categories, since they do that for accomplishing archive challenges.