Your liberal friend never read the Federalist Papers nor the writings of Thomas Jefferson.
The 2nd Amendment could have been written as:
“Guns are very dangerous to government and government does not want you to have them,(NOTE the comma)the right of the people to keep and bear arms, SHALL NOT BE INFRINGED”
There is absolutely nothing in the first clause of that sentence which in ANY way precludes us to not only keep and bear arms but also should have prevented the government from passing ANY laws on arms.
The first part could have said “The moon is made of green cheese,” and still not have changed the balance of the 2nd Amendment.
He says they're crap. So, I deduced three quick things: 1) He didn't read them, 2) doesn't believe they were really by Madison, Jefferson & others, and (most important) 3) not worth discussing with him anymore. But I still see him post on FB that the 2nd Amendment was for slave-owners, and is therefore illegitimate. Rachel Maddow's argument, BTW.