I don't think anyone is asking to banish the second amendment, just maybe not sell automatic rifles so easily.
They most certainly are, hence all the misinformation present.
It's not legal to sell automatic weapons to unlicensed individuals. "Assault" is a *** term invented to make any weapon seem scary, most are semi-automatic requiring the pulling of the trigger for each round fired.
Take the "scary" AR-15, it's not automatic but I bet you didn't know that. Nearly any semi-automatic weapon can be converted into full-automatic by modifying the firing mechanism, it's also illegal to do this without possessing the proper license.
The individual of the most recent soap boxes already possessed all the required licenses. He also passed a far more stringent background investigation required to perform as a guard for federal facilities.
The only way to of prevented him from acquiring those weapons would of been to ban all private ownership of firearms.