Alas, if they hadn't said "worthless piece of paper", it might be defensible. As it is...

(The defensible grounds, for the curious: I only accept this progression from someone else who's been through it, and who understands how hellish it was. I.e, my father could say this (especially as a professor himself), to describe the multiple kinds of shit you are put through in academia. Never, ever, is it acceptable to describe someone's work or accomplishments this way; only the obstacles in one's path, like academic politics.)