You're totally right. I'm trying to make a moral argument, I think if it were unfeasible for an individual to make something (e.g. modern CPU) then you could make an argument for producers limiting them on the basis that it would effectively prevent anyone from doing the banned thing. The fact that it's roughly as easy to reflash an IoT device with custom firmware as it is to make an antenna that produces noise in a forbidden frequency means that you are adding a technical measure to prevent just some of that illegal action and not stopping a determined hacker.

I'm not claiming it wouldn't be an overall social good, but other areas of law and regulation don't seem to function like this (with notable exceptions like photocopying banknotes).

The (particular) law isn't actually aimed at stopping those who just want to go into their garage and produce illegal interference out of malice. E.g. people can create 200 Watt space heaters in their garage easily but it'd be odd to then conclude CPU regulations wouldn't stop people from doing bad things with CPUs.

That is to say, it's infeasible the average someone will make a working Wi-Fi radio which uses the Japanese channel 14 (involves changing what is sent by the radio, not just raising the frequency... unless you want to accurately re-adjust the frequency inside of your smartphone too) but it is reasonable to expect the average someone might just load some open firmware from the internet which allows them to set the channel to 14.

I will say I agree it's different than a lot of regulation. On the other thing I think that has more to do with radio space itself being very different than most things (i.e. a shared public resource) than inconsistency.