1. You are imbuing the PCs in the game with the same in-game mastery that you have. The characters (assumedly) do not know this is a "game." They are not hyperrealistic math machines. They will suffer from the same irrational biases, small sample sizes, and preferences within the game that we do. The fighter may want to use a particular weapon because his tribe/family always used that weapon, or because he believes it looks cool, or because it is favored by the gods, or whatever.
The characters can only observe the in-game reality which corresponds to the math, rather than the math itself, but it doesn't take a master of physics to understand that a bigger weapon hurts more. It might seem simplistic, and it could even be mis-leading in some cases, but in this case it's exactly as obvious as it appears.
In real life, you might actually fight better with your particular weapon. I'm fairly confident that a real-world test would indicate that people perform better with the tool they're used to, rather than one with a slightly superior design. Real life is complicated. Likewise, I know for a fact that a game-world test would indicate that people perform better with the better tool, and comfort isn't a factor at all. The game world is a less complicated place, and for characters to treat is
as though it was as complicated as our world is disingenuous.
2. You are denigrating roleplaying over your preferred method of playing. Again, there is nothing wrong with viewing this as a game system, and you believe that every player must necessarily play it "to the best."
But that's, just, like, your opinion, man. If that is way you and your table play, then more power (and math) to you. As you are no doubt aware, other tables play differently. Attempting to assert a universal, "All tables must play this way because the in-game characters would also optimize" necessarily fails as a matter of logic, because ... um ... real tables in the real world aren't optimizing. See what I did there?
If that's where you think I'm going with this, then you don't understand my point at all. I'm
all about role-playing. If I'm guilty of one-true-way-ism, then the true way which I advocate is role-playing above all else and the absolute admonition of any form of meta-gaming. (Which is more extreme than my actual position; I'll admit that there are times when meta-gaming is the lesser of two evils.)
It's just that people have a lot of mis-conceptions about role-playing. Some people seem to think it means you should play the character as though their world operated like our own world -- which is
actually a form of meta-gaming. The character doesn't know anything about how things work in
our world. The character only knows what they can observe about
their world, of which
we only know that the rules of the game are an adequate reflection under certain circumstances.
Going back to the previous example, the characters within the game world absolutely do
not know that scimitars are better than long-swords when you're attacking from horseback. It may be true in our world, but it's not true in the game world. A test that we perform in our world, which might verify scimitar superiority under certain conditions, would have a different outcome in the game world. In order for it to have the same outcome, you would have to add rules covering that condition to the game in order to make it so -- which is also a solution, of course, because then it brings those factors into the realm of what the character can observe!
Otherwise, though, you'd be like the poor wizard who proclaims the impossibility of a twenty-foot tall humanoid, claiming that there's no way it could possibly support its own weight. You're making an argument based on information that you don't have, which isn't even true.
(I
am over-stating the assumption that you're all playing competent professionals, which is far from as universal I seem to imply, but that's only to get to the larger point about role-playing based on observable realities rather than meta-gaming.)
