First, you would need to define the term “professional game developer” to make that statement.
Based on your statement, a professional game developer is someone, who is is to lazy to read documentation guidelines.
You are mixing professional documentation writing with commenting on a wiki. These are two very different things.
Any professional (game) developer has to read and will read guidelines. This is just part of a QA process. If (nearly) no professional game developer would not do it, then explain to me, why so many professionals are contributing to first class Open Source projects then
But again, what you describe is neither quality documentation writing, nor generating API docs or creating man pages. It’s just commenting on someones input. There are no QA processes for comments, I guess.
How about the python docs?
Because they have guidelines, (nearly) no one seems to read