From the article: So I said, "Cuba has an important resource - lots of people who have never learned to use Windows. And here you are, destroying that resource, gratuitously. If you are not ready yet to switch these clubs so that they teach people free software, at least you should shut them down until they can." Does he say this seriously? I've seen people using this kind of hyperbole when in a partisan environment…
It's completely serious. Stallman thinks the social harm done by proprietary software licenses is greater than the good done by the ability to use the software. Do you think that's an unreasonable or laughable position? The consequence that it is better to close down the clubs than to let them encourage proprietary software usage is almost inescapable given the above premise.
Just imagine the amount of wealth that has been created in the past couple of decades by using proprietary software.
Though one could argue the same could have been done with free software, he's saying (as you paraphrase) that it's better to have no progress at all than to have progress at the cost of using proprietary.