I am re-reading that most valuable of biographies - Father Seraphim Rose: his life and works, by Hieromonk Damascene - and was reminded of the vast damage done in the late twentieth century by spoiled priests.
Thomas Merton - 3.5 million hits on Google search
Alan Watts - 700K hits
Bede Griffiths - 200K hits
The likes of these were instrumental in setting up and encouraging the sixties counterculture, the sexual revolution, syncretic and New Age spirituality, and the fusion of radical Leftism with the project for world government, the 'peace movement' and suchlike utopian plans for 'heaven on earth'.
The man who became Fr Seraphim was taught by Alan Watts in San Fransico during his pre-Orthodox Nietzschian beatnik era; the young Eugene Rose wrote to Merton, and followed his evolving apostasy with dismay.
Dom Bede Griffiths OSB had no connection with Fr Seraphim, so far as I know - but was a pupil and frequent correspondent of CS Lewis.
My impression is that few people have done so much damage as these spoiled priests - who brought 'inside knowledge' of what they attacked.
All were talented, learned, charming, eloquent, energetic, excellent writers - which of course only made them vastly more dangerous when they crossed over to serve the dark side.
If we add to them the numerous less famous priests, pastors, monks, friars (especially them!), bishops, archbishops and a Pope who were to a significant and crucial degree covert apostates (mostly in the sense of re-writing traditional Christianity to suit modern sensibilities) - then it can be seen that these foes masquerading as allies, these wolves in lambs' clothing, constitute just about the most important servants of evil outside of Communism (from which they were, of course, not distinct).