It's not.
Opus is already quite capable of zero-day exploits, and so it was inevitable that the next generation of LLMs would be eating them for breakfast.
This is a defensive move because Anthropic was first across the line. As soon as hostile states gain access to this tech, there will be a veritable tsunami of pwnings across the globe, as everyone wielding such power battles for the compute power and allegiance of every processing device on the planet.
It'll be a race of exploit, secret patch, exploit, secret patch as these AIs battle each other, with territory marked by the machines under their control.
And you, Joe Average, won't even see it happening, because your computers and phones and cars and TVs will tell you everything's fine while they do battle in secret.