The problem with the microcode is really unfortunate, because originally one could consider this part as “hardware, not software”. According to the FSF, everything which is updatable is software (and it should be free to save you from the dangers of non-free software), whereas things which need no updates are hardware. Of course, it’s a somewhat arbitrary line to put, but you have to put it somewhere, otherwise you cannot consider anything free under any conditions, unless you have your own manufacturing process.
With such criterion, Librebooted laptops can be considered as running fully free software, because the microcode is just a part of the “hardware”. Now, it turns out that the updates are required for security.
In this situation, if the FSF would allow (or, more precisely, endorse) the microcode updates, they would be breaking their own strict rules for the free software. They would then have to remove the certification from all linked laptops and declare that no device can run free software today. Alternatively, they can continue to consider the microcode as “hardware”, which has newly found security limitations.
Look, they are the Free Software Foundation, not Security Foundation. Their main goal is to promote freedoms of software and educate the public about it. Of course, their only reasonable choice is the second one. I nevertheless think that they should be more explicit about the problems with such choice, instead of removing all warning from the kernel. Without telling it, they put the security of their followers at risk of course. Libreboot developer also disagrees with the current FSF position about it.
So in this case, one has to choose between security and freedom, as I mentioned above. I’m using Qubes OS, so I do value security to a large degree. I decided to install the non-free microcode. On Librem 15, it’s a part of the Coreboot updates, which already were non-free. Let us hope that the microcode can be freed at some point in the future.