Because launching to a retrograde (reverse direction) geostationary orbit is very expensive in terms of fuel. (see note) You won't have much payload.

It actually takes less fuel to do a "figure 8" trip around the moon and choose to enter a retrograde orbit than to directly inject into such an orbit at launch.

It would not be hard for any major power to have a vehicle of several tons into a retrograde orbit and then release 10's of millions of small ball bearings, or other material. People have suggested sand as it would damage more delicate things such as external wiring and solar panels. Ball bearings would be far more penetrating.

Note: about 7% of the energy to get to space is "free" from the rotation of the Earth. If you want to go into a retrograde orbit, you need to add 14% more energy. 7% to undo what the Earth is already doing, then the amount you would have used plus making up the 7% you didn't get from the Earth.