Here is how Keynes "ignored" those "workaholic tendencies":
Yet there is no country and no people, I think, who can look forward to the age of leisure and of abundance without a dread. For we have been trained too long to strive and not to enjoy. It is a fearful problem for the ordinary person, with no special talents, to occupy himself, especially if he no longer has roots in the soil or in custom or in the beloved conventions of a traditional society. ...
For many ages to come the old Adam will be so strong in us that everybody will need to do some work if he is to be contented.
To be fair to Sutherland, Keynes didn't use the exact words "workaholic tendencies" so if she actually read the Keynes essay, she might have not comprehended the passages dealing with the training of "old Adam"... "too long to strive and not to enjoy." On the other hand, it is entirely possible Sutherland didn't read the essay but just assumed Keynes ignored the point she wanted to raise.