It isn't a mistake...
Ignoring the Compound Bow thing...
A lot of it is trying to make sure a system doesn't boil down to using a ton of stats.
For example... Swordmenship still needs significant dexterity in order to be an effective fighter. You need intelligence to learn the moves. You need Wisdom to read the opponent.
Yada yada.
The usual excuse as to why Bows deal damage with Dexterity is it basically is just assuming you are launching the bows at the maximum strength the strings can manage... But the damage comes mainly from being able to hit your opponent in vital locations.
Some games though do use strength.
Exalted, for example, uses Strength for damage bonus (to a limit with normal weapons... no limit if they are artifact weapons.)
Compound Bows in 3.5 and Pathfinder have a damage bonus based on strength to a limit set by the bow.
