I haven't read Saito's books, or looked too deeply into degrowth as a movement. I just read this article and thought it made some good arguments against what it claims are Saito's understandings of Marx. I'm not sure I agree with everything, but I thought it was interesting enough to share.
Well take a gander at his twitter but lets say he's a fellow traveler of LaRouche. More importantly for this though, degrowth is a bit of a bugbear for him. He complains about it constantly so I wouldn't believe he's being honest about his criticism of Saito.
ewww