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.
Not really - he already gave both. The argument is the already stated one "Emacs is not the solution to the problem of people coming to Lisp needing a good programming environment". And the reasons are what he wrote above: "because there are millions of developers that won't use it".
Now you might agree or not with the latter (I for one am in the category that wont bother to use Emacs), but it's a full argument.
>I've never heard people say 'it is unreasonable to ask people to use Android Studio to develop for Android'
People still say that, but that's beside the point.
Android Studio is a typical modern IDE, so not much of a barrier to entry. Emacs are much more arcane and idiosyncratic (and doubly so outside the Unix world, e.g. for the huge majority of Windows and OSX based devs).
Obviously interesting platforms can get away with much more ridiculous requests such as "buy a Mac" or "program in JavaScript".
Pretty much all "smart editors or IDEs" that are available are editor construction toolkits bundled with add-ons which make completed editors using the toolkit for a variety of special purposes, and with an ecosystem (first party and/or community) of additional add-ons available. Visual Studio, Visual Studio Code, Eclipse, IntelliJ and its various cousins, etc., all fit the model.
Emacs fits in with the rest in this regard (in fact, its one of the earliest inspirational models for what the field has become, probably the earliest example of the now-dominant model that is still actively maintained and widely used.)
The same is definitely not true for VSCode, Emacs or vim, though perhaps bundles like portacle can offer a similar experience. I say this as an Emacs & IntelliJ user.
It's cool, it's interesting, it's tinkering and I don't want to do it :-)
I guess neither of those is worthy of using either because of this.