I took the time to write the following because I want people to focus on the right aspects of gun control and not fall into the trap of blaming and demanding regulation for gun features when that does not prevent future shootings. Full disclosure: I am a gun owner, use suppressors, and spend a lot of time around military and firearms. I am also pro-gun regulation - as long as it is based on facts and WILL prevent shootings versus just to temporarily soothe an emotional response or appeal to a voter base. Shootings are horrible. It makes us all upset. We have to work harder and do MORE homework as individuals rather than just demand that our uneducated representatives take up the fight for us and rush bills through.
****TLDR; Banning gun accessories is a way politicians appease their voters without tackling the real fight: meaningful regulation that prevents mass shootings.****
Illegal suppressors can be manufactured within days and with parts from home depot/amazon for minimal cost ~$100-200 on the high end. They are far far easier to make than a firearm. Anyone who wants one and doesn't care about the law has one. Legally acquired suppressors by comparison are incredibly inconvenient to get (13+ months right now), require fingerprinting and passport photos, and are ludicrously expensive for the tube of stainless steel/titanium that they are (more than a decent AR15 rifle). If you take away the highly regulated means to get them, you just piss off a lot of people that follow laws and only encourage the rise of garage-manufactured gun parts. Remember - this is something that anyone who can build an IKEA shelf can make on their own - for less than the cost of an IKEA shelf.
Past school shooters wore black trench coats because they thought it made them look cool - it was part of their identity. This VA Beach shooter may have thought that having a suppressor on his firearm would result in his attack being more effective (or more likely, based on why 9/10 people I know have bought them, they are a luxury purchase $500-1500 to make your gun look cool). Just because a deranged murderer has a personal opinion about something doesn't change the facts about what it is or does. The average person's perception about these very specific tools is extremely skewed by wildly inaccurate movie and tv representations.
Three schools I attended (high school, community college, and university - all in different cities...fml) have had shootings, and in all of the cases people reported that they heard all kinds of sounds but never imagined it to be gunfire. That includes me. I have spend decades around gunfire and my brain still refused to accept what it was hearing because I wasn't in an environment that fit the unfolding scenario. People's minds do not want to accept what is happening - that is why people often stand around for a moment after witnessing an atrocity right in front of them and do not start to panic or run until they pick up on social cues from others who react sooner.
Guns are easy to acquire in this country and still have tons of misinformation spread about them. Suppressors are very difficult to acquire and have even more inaccuracies circulating. The vast majority of suppressors on the market are designed and marketed towards recreational shootings, and they ARE primarily designed to reduce hearing damage and felt recoil for the shooter. Stand next to the shooter - it is as loud as a jackhammer but won't blow out your eardrums. Stand out to the side or down range and it is NOT hearing safe (140+ db). In testing, blindfolded individuals were more accurately able to point in the direction of the suppressed fire than that of an un-suppressed firearm. Unless using subsonic ammunition (which has less stopping power/effective range), there will also still be a supersonic crack of the projectile breaking the sound barrier, regardless of how much sound is mitigated at the shooters position.
Several extremely progressive socialist nations in Europe with much more strict gun control than the US sell suppressors over the counter same-day. They are focused on preventing deaths - not pissing off hobbyists.