It is the same kind of human rights issue, I agree... but...
Iran is a different matter altogether. We aren't obligated by our debt to Iran like we are China. In fact, Iran probably owes us a little. We have no reason to continue trade with Iran, what little we have, because we have no obligation of debt to them. The same can be said for Saudi Arabia, except in their case, they have the oil we need to keep our society moving. Unless you want to live in pre-automotive times, or drill for domestic sources to replace their oil, there isn't a practical solution. Because America has become fat and lazy in manufacturing and production, we depend on trade with other countries, like 'em or not... that is just how it works in the real world.
Oh, they will get paid, as long as US Treasury Bonds are worth anything. If they become meaningless paper, we aren't going to be concerned about human rights abuse in China, I assure you of that. Oh, I will laugh on that day too.... because if the whole world has gone insane, I may as well join the crazies... my laugh will be one of those hideous creepy insane man laughs... bwhahahahahahahahahaaaaaaaaaaaaaaaa!