Did you actually mention any of these disadvantages? Most often I see the attitude you describe when someone says "I tried haskell/lisp/ocaml/scala/clojure but it isn't practical". And that's it. No explanation of what their problems were, just "nope, it obviously can't be used for anything practical and you must be crazy if you think you can use such a language". After seeing that kind of nonsense enough, it can be easy for somebody to fall into the trap of assuming you didn't really try it either if you don't bring up some specific problems.