Sigh!
From the Oxford dictionary of English:
Impotent : Adjective - Unable to take effective action; helpless or powerless: "He was seized with an impotent anger."
Obviously 'impotent' in this context referred to their inability to perform their professional duties, not their performance in bed. It is very commonly used in that context. To mean helpless, ineffective, incapable, weak, worn out, inadequate etc.
Why don't you look up a dictionary, before fuming and venting with impotent anger? (And no, by that I do not mean frustration after a failed lovemaking session.)
