What are your opinions on the ATF "bans"? (FRTs, pistol braces, etc)

I had an interesting conversation with a coworker today. For context, he's fairly right leaning and (if you haven't guessed) I'm not. Our conversation started off as discussing the pistol brace ban, and both of us agreeing that the ATF ruling pistols with a brace as SBRs was absolutely dumb.

Where things diverged was as the topic drifted to FRTs. I told him I was on the fence about them, as I understood that while they didn't not fit the definition of a machine gun, I wasn't a huge fan of devices that increased the ability to shoot a gun at (or near) full-auto cyclic rate. I know it's a ton of fun (I've done it before) but aside from fun, I can't see a good justification for a civilian to have a weapon that can shoot that fast.

He tried to argue back that any regulation (or ban) like that was a violation of the 2nd amendment and that since the introduction of the nfa it has been nothing but an ever tightening grip of regulation and "bans" on law abiding citizens.

Our conversation was cut short by work, but I'm curious for the rest of my fellow LGOs, what are your opinions?