If you have offensive capacity you will be bound to use it.
Guns don't kill people, People kill people. Sure, but guns make it much easier, and by design, have the capacity for landing in the wrong hands.
Are you suggesting people who own guns should kill someone from time to time so nobody will fuck with them?
Over 50 million households in the US own 200 million or more guns, collectively. If these guns were usually used this way, the US would be depopulated by gun violence in a decade or two.
I mean, the whole point of a patent is to be able to sue people who are competing with you. How can that ever be defensive?
If IBM is not deterred by Microsoft's patents, why would they be deterred by mine?
If your next question is that the existence of your invention would invalidate their patent due to prior art, that would take costly legal maneuvering to establish. Is there a shortcut around that legal maneuvering? Yes, patent your invention first.