The author is an interesting character of strong, often contrarian, opinion. He's also the guy behind the Calibre e-book software, which was largely written in Python 2 long after that was deprecated. He even wanted to maintain Python 2 himself rather than rewrite Calibre, but he eventually realized that wasn't feasible and ported Calibre to Python 3.
This reads as if he started Calibre when Python 2 was already deprecated..but to be clear, it was started some years before the first release of Python 3, 14 years before the deprecation.
And at the time of the beef, many bigger apps were not ported yet (some even till today). The authors' opinion was more an extremer version of something the whole community felt at the time.
Also realized this when trying to get terminus to work. I like the simplicity of foot in wayland and st/alacritty in Xorg. I wish I could find a terminus replacement and I do give it a few hours each year but still haven't had any luck...