What I notice is that all of the advice for pullups is very different from other exercises. Recovery is never mentioned, it comes down to doing lots of pullups, many days a week, through the day.
Bodyweight exercises like pull-ups and push-ups are intended in some programs to increase muscular endurance more than muscular strength. Untrained people will gain more muscular strength than endurance initially when they train pull-ups. But once the untrained reach the level of strength needed to do pull-ups for reps, they won't be overloading their muscles to make further progress.
I'm not exactly sure, but my guess is that recovery for muscle hypertrophy and strength gains is much more critical than that for muscular endurance gains. Still, a drill sergeant can run even the most scared basic training recruits into the ground if he pushes them too hard.