The funny thing for me about this popping up from time to time is, that I like both Tcl and Scheme a lot. Each for their purpose. While certainly not beautiful and never ment to be an implementation language for large-scale applications, Tcl does a wonderful job for its designated tasks. The syntax might seem bizarre, but there is actually a great and simple system behind it, I strongly recommend to read the chapter about the syntax in the book by Ousterhout. Like Lisp Tcl is actually a homoiconic language. And like lisp you can create your own syntax, as required. On top, basic control like function calling, looks more like natural language, little syntax required.

Of course, as programming language, Scheme is much better, and it is the language I use for day to day work. In that respect Stallman is right. However he missed a few important points and that is why Tcl is still so popular, probably more so than Scheme, if you just count users. Tcl didn't just bring a language to the table, it also has an excellent implementation which always was freely available and could be embedded into any software project. It has a nice range of very powerfull tools, Tk obviously the most fameous one. Still today it is one of the most popular GUI toolkits. And that is where Stallman with the GNU project failed. Had they at that time or in the following years provided a comparable Scheme implementation, it would have been extremely popular for application writers. Assuming of course, that it had been licensed under LGPL so that any application could use it. But it took most of the 30 years after this post for Guile becoming an option there.