The author doesn't owe the general public a FOSS product. The source is already freely available, which is better than nothing.

For a relevant example, consider Adobe- they are actively hostile to sharing source code. Complete capitalist jackasses, yet Adobe doesn't generally get a hard time about it on HN or elsewhere.

Just because someone says it, doesn't make it either true, or even sensible as "this is how it should be". Unless you can back up that statement with strong arguments (which RMS can't, ideology doesn't pay real world bills, and unlike RMS, the rest of us don't get paid lavish speaker fees) appealing to authority does nothing to strengthen a position.

Just because RMS says it doesn’t mean it’s true.