In Confessions of a Barbarian: Selections from the Journals of Edward Abbey, 1951-1989, I find this from July 7, 1977:

Letters I Wrote That Never Got Answered:…

“Dear Gary [Snyder], I like your stuff too, except for all that Zen and Hindu bull…”

You know what — yeah (except that Gary Snyder’s account of living in a Zen monastery is pretty good journalism, and worth reading).