You are just stating it. Without any reason. One can't argue against a statement, you have to provide reasons behind your statement for there to be an argument.
For example: "Asking people to use an editor where C-c doesn't copy and they have to relearn the keybindings is an unnecessary barrier of entry". I would agree with that and note that as a stop measure they can use the mouse for most tasks so they can postpone learning Emacs until they have learned CL.
If you are on OSX CCL has an alternate IDE that's pretty good. Otherwise you can pay Lispworks or Allegro. Yeah it would be awesome if there were a multitude of IDEs, but people are not going to write IDEs for environments they don't use for free, it is unreasonable to expect that.
I've never heard people say 'it is unreasonable to ask people to use Android Studio to develop for Android' so I'm not inclined to agree that it is unreasonable to ask people to use a Emacs to develop for CL. Especially after Shinmera has gone to great lengths to package a pre configured version. I know of a recent lisper that just uses Emacs for CL without previous Emacs exposure. It is an unnecessary barrier, but not more than a hump.