This is because we've been trained to be humble by the machines we work with. Computers expose a lot of our mistakes, and over time they remove any illusion that we can be quickly confident about things.
I would take the qualifiers in his post as an indication of his general disinclination towards making absolute statements, not as a lack of humility.
That's unacceptable! Bring out the surgically precise praise!
Bellard did multiple breakthroughs: ffmpeg, qemu, tcc, jslinux, a state of the art FFT algorithm. I probable skipped a few.
With all due respect to carmack, a single ballard's projects would put anybody into the eternal hall of programmers fame right next to Linus, Carmack, Stallman, the Bell labs crowd and others.
i do understand how carmack did what he did logistically (time, effort, skills, compensation)...
Fabrice is just out of this world. When? How? Why? No idea.
https://bellard.org/pi/pi_bin.pdf
Though I have to say the last line of the proof "...which gives (1) by reordering the terms" took me much head scratching to understand!
Fabrice is more clever and faster, I guess.
But John Carmack is in my mind a better software engineer. He writes elegant code that can be used and maintained for a long time. At least from Quake 2ish, but you can see signs of solid code architecture already in Doom.
Doom code will live almost as-is forever. The code Fabrice wrote for ffmpeg has been entirely replaced
2) avoid qualifiers in personal compliments (unless ironic)
(Especially if you are complimenting a person with ADHD.)
It’s also a nod to his own fame.
[1] This is based on Masters of Doom. And the anecdotes are probably from the 90’s. And being arrogant does not mean that being confident in one’s ability is unjustified or that they are in fact not skilled. Being arrogant and being highly skilled are completely orthogonal.