This is pure ignorance and or thinking it can be done like shown in TV shows or movies. Any bio-weapon that is effective would be a virus/bacteria that is propagated via air particles like Antrax. That's not something you can build in a shed because without the safety precaution the person creating it would be the first victim of it.
I have relevant professional experience but do spout off.
> That's not something you can build in a shed
A negative pressure enclosure, filtration, and UVC sterilization can't be built in a shed? On what basis do you make this seemingly absurd claim? Go check out what hobbyist mushroom growers commonly get up to in their back yard.
BSL-3 is far from technically complex. It's just safety critical to an absurd degree thus (rightfully) mired in bureaucracy.