This is a bit different from flak. The intuition you have for kinetic energy based on living on earth doesn't capture just how insanely high the kinetic energy of something going at 70 km/s is. It's probably better to conceptualize it as heavy artillery than a projectile in terms of the damage its capable of inflicting.
Sure, but it will also go straight trought many things, not impart all of its kinetic energy into whatever it punches through first. The ISS has survived quite a long time in much the same environmental conditions as stuff on the moon offer, and the ISS also needs to worry about keeping air inside.
Just how dense are these rock showers do you reckon? After all, the moon has very old untouched features.
The ISS can first of all move if something larger is detected. But the ISS has gotten hit, several times. But most of its cross sectional area is solar panels though so it's not been so bad.
Another big difference is that if the ISS gets hit by anything with significant kinetic energy, it will just punch a hole clean through whatever it impacts. There is nothing that can absorb that sort of kinetic energy. This is in most scenarios good news.
If a meteorite hits the lunar surface, the surface absorbs the kinetic energy, the surface and the meteorite evaporates, causing an explosion of molten rock moving at high velocities. This means even glancing hits or near misses can be devastating in a way they aren't when you are in orbit.
