I am a manager as well, and I just recall that there are only so many hours in a day and I couldn't have written all of that code myself. But that's for suboptimal code, not atrocious code.

I haven't dealt with people under me who write truly abysmal code so far, mostly because I am a picky hirer, but that subpar code that my people have written is my fault, because it's my responsibility to make them better programmers.