They're not saying devices shouldn't be programmable
That may not be their goal but that is what they are saying. The position of the FSF is that a device whose closed source firmware cannot be upgraded is superior to one that can be upgraded but for which only closed firmware exists. So, if you are buying proprietary hardware (and you are in 2025), you should prefer the closed hardware which is not programmable.
It is a stance that only makes sense if you care more about the simplicity of your message than the implications of your position.
They are directly creating demand for less open systems that provide less freedom. It is dumb.
The solution is simply to have a sane definition of “free software” that does not include firmware.
There should be a Free Hardware Foundation that calls for hardware to be free. They can demand that everything be completely open which most of us would support and may even be possible now that we have RISC-V. Their list of “approved” hardware could be essentially blank. That said they could participate in creating some. Of course, it would likely be worse at first. You know, like Free Software was bootstrapped.
The FHF could object to all non-free hardware while still acknowledging that programmability is a positive step that at least has the potential to be more open. The FHF could sponsor or endorse free firmware efforts.
That clarity would allow the rest of us, even the FSF fundamentalists, to make sane choices.