Feser does a predictably fine job of defending himself, but I was taken by some other things Blackburn says.
"Functional explanations of the prevalence and survival of religions are not calculated to appeal to practitioners themselves …"
This would come as a surprise to Rudolf Otto, author of The Idea of the Holy. Otto was a practicing Lutheran."I suppose that later ages can always be said to have inherited something from the past, but otherwise this is a bit like supposing that republicanism is a vision inherited from monarchism."
Well, there is a connection between the two. See the history of the Roman Republic.