Does the size and strength of a creature effect the range increment of thrown weapons? Or does a Strength 5 gnome throw a dagger the same distance as a Strength 35 cloud giant?
The giant is probably also throwing a dagger that's about the size of the gnome. So having the range be independent of size makes a fair amount of sense.
The difference in range of a raging human barbarian (Str 28) and a human wizard (Str 7) isn't as clear. You can compensate for a low release speed by throwing in a higher arc. That works up to a certain distance, so for the best realism, the maximum range should depend on strength. Tossing the weapon higher is probably also more difficult, so I could easily see a decrease in the range increment.
On the other hand, I'm not aware of any arguments that thrown weapons are extremely powerful, so you're probably looking at a backup or emergency weapon. Keeping the range fixed for any character also makes it simpler.