Bioweapons are the most difficult thing to pull off out of all possible attack vectors. A rogue nation state could obviously do it, but they could also do any other number of equally harmful attacks, and none of it requires AI.
A non-state actor is another thing entirely. It requires the right lab equipment, the right lab know-how, the ability to develop the weapon without killing yourself, the ability to not get caught, the ability to buy the right regulated materials, and the list goes on.
Yeah, the world should tighten the security of that industry, but let's not make this an AI fearmonger talking point.
I'm also confused why everyone is so much more afraid of that than... say... a group of terrorists dumping millions of nails into a few major highways across the country. Easy to pull off, doesn't require coordination, cheap, causes billions of dollars of damage and makes people think the terrorists could be anywhere. Like what are they going to do, arrest every construction worker?