The lwn.net article linked in this post has an excellent, seemingly neutral summary of the issue that casts a lot of light on TFA; I highly recommend anybody interested in the OpenPGP schism read this.
This was my first thought too because the argument is against a FSF-award-winning founder and maintainer of 25 years of one of the most important and widely used cryptographic libraries.
The blog appears to be at least hosted by, and possibly written by Andrew Gallagher[1] <andrewg@andrewg.com> per [2], [3] and [4]. Is there meant to be someone else behind the "we"?
There have been some tensions between some sequoia-pgp devs and Koch (which are mentioned in tfa). So it might also be some of them. I don't know anything first hand tho.