It's because handguns were originally on the NFA, and they only got dropped because it was holding up getting it passed.
I am not sure that was correct. I don't think handguns were ever considered.
But the SBR and 'barrel length' thing was a response (along with most of the NFA) to the prohibition gang wars of the 1920's and the Bank Robbery scourge of the 1930's. In both cases, the sawed-down shotgun, the sawed-down BAR or rifle, etc. was a weapon of choice. And so was an easy target, especially as folks were decrying 'No Sporting Purpose' to something like a 12" Greener double.
Well yeah, no sporting purpose to a coach gun. But plenty of purpose in bandit country!
NFA was all about appearing to 'do something' to stop the Dillinger/Pretty Boy/Bonnie-Clyde, etc violence that was getting massively hyped up during the early depression by the media (selling papers and radio broadcasts) and Hollywood, which was only to happy to sensationalize all of it. That the Roosevelt Admin got the added benefit of reducing the possibility that an armed Communist/anarchist/fascist uprising (that they could not have hoped to fight effectively) might arise in the Depression... was an added bonus.
And over the decades "Blame the Gun" became a Democrat mantra. Along with watching how Stalin and Hitler and Hirohito (Japanese had forbidden private weapons ownership for decades) could so easily cow an unarmed population and force regulations, social engineering, etc. on them... made removal of arms from the population a natural path for a party that wants to elimiinate personal freedoms, states rights and individual responsibility... in favor of a nanny state that will dictate every aspect of life... cradle to grave. Which is what the socialists who started hijacking the Democratic Party as early as Wilson... are all about.
These are not Andrew Jackson Democrats. They are Marx/Engels/Leninist/Maoist/FOCO types who found it convenient to hijack a party with 200 years of history... because noone wanted the shit they were being fed by the Red Book-carrying commies who said "Give everything up for Utopia..." when what humans really wanted was a Porsche, a big house and a nice boat -- which are the symbols of individuality, success and personal freedom.
Guns protect those. The NFA was the original 'Camels nose under the tent." Unless, of course, you want to include the Southern Democrats forbidding blacks from owning guns in the pre-Civil war and Reconstruction era. Because they knew the way to keep a population oppressed was to keep them disarmed and terrorized. And, of course, New York's Sullivan Law, which was largely designed to keep the sub-human Irish and Italian and Slav populations flooding the city... from being armed. And remember... the Democrat Machine came out of New York. They were well aware of the Sullivan Law....
Anyhoo.... I ramble on. We'll see about suppressors. In the EU, you can walk into any store and for less than $50 walk out with a suppressor with no paperwork at all. The same asshole politicians who bray on about how 'progressive Europe's gun laws are' have no fucking clue.
At this point, it's all reactionary anyway. Instead of looking at suppressors as a benefit (hearing protection, not annoying Karens in increasingly congested rural areas... therefore cutting down on useless LE calls and responses), hunting and culling species in urban areas... it's all about "If those rednecks want it, we're against it and we're going to punish them because they aren't bicycle-riding 15-minute city, tranny-loving socialists." So they are going to 'get them' any way they can. From making pickup trucks that suck... to finding ways to shut down farms and move us rural "Kulaks" into state communes and hive apartment buildings.
Sort of sounds like a couple of countries where the people are miserable and would have risen up. Except they didn't have any %$#@ing guns.
Sirhr