I don't know if it's worth going on the defensive about that kind of stuff.
If the founder made an in-depth reply explaining that "No, we don't suck, we use language X, framework Y and methodology Z", then that just opens up a pointless side discussion about whether the X+Y+Z stack sucks, and how much exactly.
All that will remain in search engines, so in a few years' time the company will appear in public searches as a company that uses X+Y+Z even if they have moved on.
You're missing the point: if you're going to respond to a matter like this publicly, you had better respond substantively. Anything less can have the effect of making the claims against you seem more credible.
Note that this wasn't a debate about languages, frameworks or methodologies. The OP flat out referred to the company's code as "tangled mess of mindless duplication, half-implemented features and misleading comments" and claimed that only one employee "knew anything about the system." The response here mentions surfing on Wednesday but doesn't dispute any of the OP's claims about the state of the company's technology and technology organization. That looks horrible.
If the founder made an in-depth reply explaining that "No, we don't suck, we use language X, framework Y and methodology Z", then that just opens up a pointless side discussion about whether the X+Y+Z stack sucks, and how much exactly.
All that will remain in search engines, so in a few years' time the company will appear in public searches as a company that uses X+Y+Z even if they have moved on.