The article doesn't establish whether AI ultimately benefits attackers more than defenders. Open weight models give defenders access to the same capabilities. At the very least the community has a level of symmetry they wouldn't otherwise have.
Right now, we are in this transition phase where models discovers tons of latent bugs everywhere. That makes it easier for attackers of course to find a single bug, and lots of fixes means lots of things to reverse-engineer in the patch-gap. But that won't be going on forever, as the number of bugs to find here are finite. Assuming that we use the same models/techniques to scan all commits being made, we'll end up with a codebase that is much much safer than what we had before.
Excluding the modern equivalent of a script kiddie, even a "budget" attacker will have for sure invested enough to run a serious model (GLM 5.3 in this case, which requires hundreds of GB of RAM).
On the other hand - the defense - there is a large spectrum, and that's where the problem lies. There are surely companies that can defend themselves (either via cloud solution with granted cyber capabilities, or on local powerful machines), but there is a large amount of people that don't even know how to run a local LLM, let alone compile a program like Firefox.