To be safe from monsters, humans would build fortifications.
In order to throw a spear with decent force, the thrower must take at least three steps to gather momentum, which makes it impossible to throw it from the walkway on the top of the ramparts. For the same reason, a spear can't be fired from cover, or through a hole in the wall, or a machicolation:
In the thick of the woods, or in a monster cave, a spear would perhaps be too long, awkward to maneuver, it would bump into obstacles. But an archer is much more maneuverable, and can hide behind a bush, even shoot through foliage without being seen.
In all these circumstances, your overpowered humans' ranged weapon of choice would probably be a heavy bow with heavy arrows.
Now, there's the atlatl. Throwing spears that are propelled with an atlatl are essentially longer arrows. They are lightweight and flexible:
They must be springy. When thrown, the spear bends, storing energy, then it springs forth. This gives it a higher speed than a simple throw, but it means it can't be used as a non-throwing spear to skewer someone: it would be too flexible and wobbly.
Combat spears used as a two-handed weapon have to be stiff, therefore heavy, therefore hard to throw.
The wounding ability of a projectile depends on its kinetic energy, so a light fast projectile beats a heavy slow one.
Now... your super strong humans would most likely be using crossbows instead.
The crossbow has many advantages. It requires much less training than a bow, anyone can be accurate with it pretty quick. And it allows a huge draw weight with medieval materials. Its main issue is that it is heavier and slow to reload, because normal humans are not strong enough, so they have to use a winch. However, a super strong human would just pull the string back while inserting a new bolt, making reloading much quicker, a second or two. Weight would also be much less of an issue.
Throwing spears also have the ammo issue: you can't realistically carry more than one. Where will you put a bunch of 2m long spears? In a quiver on your back? It has to be a two handed weapon, or it will bump into absolutely everything, get stuck into door frames, etc.