Open models are crucial to protect ourselves against other AI attacks. Otherwise it's just going to be criminals, government, and other nefarious groups using them against humanity with no real defense. The Pandora's box on AI has been opened. Now we must deal with it. Burying our heads in the sand under restrictive policy is the worst reaction..
I wonder if you also believe that everyone should have nuclear weapons? And if not, why not? The main argument I can see against it is that nuclear weapons are “purely offensive”, but as we can see since 1945, nuclear weapons are actually defensive technology. Nations that have them are typically shielded from existential military threat.