Sans the explosive warheads, literally all of the fairly new, revolutionary drone tech being used in ukraine right now is civilian tech, and can be improvised pretty trivially by any small group of people with some kind of engineering background.

It's a damn good thing that terrorists and pissed off political agitators have apparently not realized – just yet – that you can just strap an IED to a cheap FPV drone off of alibaba and start running around assassinating politicians from concealed positions 1km away or whatever. Or just drop pipe bombs from a heavier hexa / octa copter a la Ukraine: heck, the designs and release mechanisms that Ukraine is using for their jury rigged grenade / mortar shell delivery drones is practically open source at this point.

Anyways the Shahed isn't even 21st century drone tech; that thing is just (more or less) a mid-sized hobbyist RC plane kit, packed with explosives, that uses GPS to navigate towards a preselected geographic target. Literally just an ad hoc WW2 V1 (and with a similarly terrible accuracy rate), but built with mostly off the shelf parts that anyone in the west (or in iran, apparently) could acquire and build given sufficient time and engineering resources.

No two bit terrorist is gonna engineer and build a shahed though: much, much easier to just build (and test) pipe bombs or whatever. And the issue, again, is that you could literally just strap a pipe bomb to an FPV, and have a fairly accurate guided munition that any idiot off the street could use.

Technically speaking, yes, just about any sufficiently motivated individual could probably build and launch a shahed by themselves – but you'd have to be a pretty particular kind of terrorist wierdo to want to and be capable of doing that.