You can use a lot of missiles to destroy any spacecraft easily, while creating a big mess. But this is not really true for the deorbiting part: satellites are not planned for high velocity impact. So either you have a low velocity impact but you delta-v is not high enough to change significantly the orbit of the debris, or you go full speed into it, and explode everything into thousands of small debris, with very random orbit.

The net is just a technique to catch a debris. After it is caught, you have many different ways of deorbiting: either the net has a solar sail and deploy it, or it has a small propulsion system and uses it, or if you hook the net to your de-orbiter, you can use the tether as a sling to release the debris in a shorter life orbit while your de-orbiter is raised to another orbit where it can find its next debris (the most promising system, but the sling part will be quite difficult to master)