You'd be surprised, and frankly it might be the only logical way to do so, ever heard the expression 'beat fire with fire' if you created something like Skynet, considering it can basically inhabit any computers on the planet, like they mentioned in T3, creating another AI to fight it would reliably be the best option available. You need to have something that can fight the AI in the Cyberspace to be able to hunt down any specs of Skynet to end it permanently.
Its the part that was sensible in The Sarah Connor Chronicles, the notion at the end they needed an AI on their side to beat Skynet, except they decided it somehow required for said AI to take the body of John Connor's Terminator Waifu. Which was the part that clearly was meant to force a continuity to the series that never happened.