Probably a similar effect that moksly said upthread about javascript vs python:
"Everyone knows JavaScript, but not everyone use it by choice, giving you a higher than average ratio of people who both dislike and know the language."
The only people using Clojure are those who really like it.
From my end, the worst things about Clojure were the JVM (making installation/configuration hellishly frustrating) and the poor error messaging (making debugging the configuration extremely difficult).
