I think you're taking a pretty bad approach to this, consider the following:
If you were to take 1000 new players and observed their gameplay, they would (after a long period of time, granted) discover by themselves that crouching does mean higher knockback forces, they would discover it completely by themselves, without the help of anyone else or any preconceived ideas, I think that's pretty much why everyone is telling you that you're wrong, they have experienced first hand the thing that you're questioning (making smug/snarky comments does not help your case either)
I appreciate you going through code, but there are massive flaws in your reasoning:
- The code base is huge, I doubt you could map a mental model of any major component this quickly
- Have you compiled the code ? Have you made modifications proving your understanding is complete?
- We're talking about C++, literally any component could modify memory directly
- Shit just isn't that black and white, VALVe are known to do a lot of "game feel" type of development, just because the behavior you're searching for isn't explicitly defined in code doesn't mean it wasn't implicitly programmed because it "felt better", that doesn't make it a bug, jesus christ