It's not about how hard you pull as much as how carefully you can aim, at least that's how I justify it in game.
Shortswords are a finesse weapon, which are the swords which can benefit from dexterity in real life as well as in game. Longswords are heavy and quite difficult to swing, so their use is based on strength.
Longsword are not heavy, and they're very easy to swing because of how they are balanced around the hilt.
If you ever swung an axe or a hammer you would understand that even those are not about strength, although with those strength help much more because they are not balanced. But the war versions of these weapons are lighter than you would think still.
You really need both upper body strength and control, but consider something like a medieval longbow with 500 N of draw force (for example). You'd need to build muscle specifically for the movement required by the weapon. Longbowmen exterted enough strain on their arms and fingers that you can tell their skeletons apart from other soldiers.
I saw a documentary where they explained how they found out just from the bones who was an archer and who wasn't. They were quite literally build different. Without enough strength, you can't shoot precisely. At least with a big hefty bow.
Longswords aren't difficult to swing and weigh around 1kg. Large two handed swords weigh around 2.5 - 3kg, and those are the giant ones you see really buff knights wield in movies.
RPGs don't make sense. Leather armor didn't really exist / wasn't widely used. A dude in full steel armor isn't almost immobile / doesn't become a turtle when pushed over. It's all game mechanics someone thought up.
Various forms of leather armour have been used by many cultures forms of leather armour extensively for thousands of years.
Leather armour has been one of the main component of armour throughout human history.
In western civilization it fell out of popular usage around the 14th century in favour of quilted armour. However, leather armour pieces were still often used in conjunction with metal armours.
Someone in true full plate armour lacks the motion of half a quarter plate. Full plate soldiers and knights were extreamly rare in battle. Full plate was either used in ceremonies or jousting, with half plate more common in battles.
If you were to fall down in full plate it would take an above average person several minutes to roll over and push themselves up. Every action in full plate uses 3 times the amount of energy.
Dex should be a bonus for your attack roll, Str a bonus in the damage roll if you succeed, for or all attack based weapons.
Exceptions for stealth attacks that can be performed, which switch to using dex for both, and cleaves which can use Str for both.
Stealth attacks are effectively a finessed "hit them in the vital spot" style attack.
Cleaves are a "I swing so hard I ignore your defense and try to cleave right through it, fuck your armor, I'm stronk"
Mount and Blade uses STR for bows, if I remember correctly
It's all because of Tolkien! He made those elves graceful and adept with longbows!
Tolkien made the Noldor (ancestors of the Middle-Earth elves) basically a race of bodybuilders swinging massive axes and hammers. They are described as tall and strong, and loving to build and craft, a race of smiths and builders. They're very much not the lithe-and-slender bowmen of D&D.
Tolkien's elven bows are often described as shooting (much) further than others. You don't launch an arrow a greater distance by aiming it carefully, you do it with by making a heavier bow and pulling back harder.
Don't blame this one on Tolkien, it's 100% on Gary.
