One should not sell bombs to a government that abuses human rights, which means murders a man without using one of the bombs.
If Saudi Arabia had murdered a man using a bomb, it would be fine to sell Saudi Arabia more bombs.
But Saudi Arabia murdered with a non-bomb weapon, and so shouldn't have bombs anymore.
One should, in fact, bomb people whose government abuses human rights, which means murders children without using bombs.
Syria allegedly killed children using chemical weapons, and so Syrian men, women, and children should be bombed.
Killing millions of people in wars, year after year, as long as it's with bombs, is justifiable because the Good War was justifiable because although the war killed some 80 million people, about 13 million of them were killed in German camps which doesn't really count as war and is therefore not justifiable, especially for 6 to 9 million of them, although those are precisely the ones who could have been very easily spared by permitting Germany to expel them, something none of the governments whose warmaking justifies all future wars would agree to.
The warmaking that justified all further warmaking consisted largely of bombing people's houses, which was therefore not a crime in the post war trials. Rather than a crime, bombing people's houses is a form of law enforcement.
Saudi Arabia is not in need of law enforcement, because it buys lots of bombs. It does, however need to be cut off in its supply of bombs.
Or, rather, it would if it weren't for the fact that it buys so many bombs. Because, although military spending reduces jobs in comparison with any other kind of spending or even not taxing money in the first place, the United States will not engage in any other kind of spending or stop taxing the people who can't afford it, and so it's a nation of war jobs or no jobs, and jobs justify mass murder as long as it's with bombs.
And so, arming dictatorships around the globe is a national duty because the Homeland nation gets armed too, which creates jobs in a society that respects human rights apart from leading the world in locking people in cages, and also being a nation that executes prisoners, and which has police engaging in murder with near impunity, and the government joining only five of the United Nations' 18 major human rights treaties, fewer than any other nation on earth, except Bhutan (4), and tied with Malaya, Myanmar, and South Sudan, a country torn by warfare since its creation in 2011.
But there's a difference. When the United States government violates human rights, it is all part of protecting your security. In other words, it is done in the name of preventing the United States from being bombed, which would be the worst thing imaginable.