Yeah, uh, I don't think he was mocking a lack of technical knowledge as you seem to have interpreted, rather the terms of 'assault weapon' legislation.

Basically, assault weapon laws in the US define 'assault weapons' as semi-automatic weapons able to accept detachable magazines and having a certain number (depending on which state, 0-2) of banned characteristics, derisively called 'scary features' as they have no real functional impact on the weapon but are associated with popular imagery of military weapons. These features include protruding pistol grips, barrel shrouds (enclosures which surround the barrel, to prevent the shooter from burning themselves), threaded muzzles (to accept accessories), bayonet lugs, folding or collapsing stocks, or grenade launchers (because... something, I guess).

In practice what this means is that there is a laundry list of characteristics with have negligible impact on the performance of a weapon, but distinguish whether it's an ordinary rifle or an assault weapon.

For example:

https://thejacknews.com/wp-content/uploads/2017/10/semi-automatic-weapon-not-machine-gun.jpg

These are Ruger Mini-14s with various configurations from the factory. Under the assault weapon laws currently in states like Connecticut and New York, the bottom-left and all three in the right column are assault weapons. The top three in the left column are not.

These rifles are all functionally identical to the AR-15. Same caliber, same mechanism, same magazine capacities, same everything. In states that have enacted assault weapons laws or more specific efforts to ban AR-15s as a response to the negative publicity surrounding them, many shooters have purchased Mini-14s and other rifles which provide the same functional capability, but in a completely legal non-assault-weapon package. Others choose to purchase 'New York legal' AR-15s:

http://www.reno4x4.com/attachment.php?attachmentid=49180&d=1392151478

Gone are the threaded muzzle, pistol grip, and collapsing stock. Same rifle. Same operation. Different accessories.

The Department of Justice did a study on the 1994 Assault Weapons Ban when it expired in 2004. They (https://www.ncjrs.gov/pdffiles1/nij/grants/204431.pdf) concluded that the ban itself had little effect on crime, as the specific terms were easily circumvented, and the majority of firearms did not fit the 'assault weapon' category to begin with. In the years since that ban, firearms design has shifted towards modularity, making it easier to create compliant configurations, and a whole market has sprung up around toeing the line.

So, in short: They banned features which were aesthetically associated with military weapons (ie 'black and scary') but which had little to no effect on lethality or suitability for a mass shooting and were easily bypassed. And now that it's even easier to bypass, this is the kind of legislation that they want to bring back, for... some reason. A lot of people think it's like you said, that an assault weapon is something functionally different and more lethal than an ordinary rifle, but in practice this isn't the case.

Turns out there was (http://www.bbc.com/news/world-us-canada-43164634) an armed police officer at last week's shooting. He arrived at the building where the shooter was 90 seconds after the first shot was fired, but did not intervene.

I think it best to research for another 20 years. That will raise all the dead.