I am not familiar with the source of this quote, but I don't disagree, it is just incredibly reductive. Gilles Deleuze him-/her-self was not born and did not live in a vacuum. They were influenced and mimetically reproduced ideas they were exposed to, like we all do. I don't find the point of this project meaningless myself. The opposite in fact. But the results are not accurate for anyone who has actually read any of these texts.