>I would think that we learned something from WW2 about this - ya know not a good idea to sit idly by and not do anything when such things start to happen. If you think the only time the USA should stop genocide is when it's a USA citizen being killed I don't see why anyone would think that is wise.

Genocide is a convenient buzzword, but does it apply here?
Syrians are killing Syrians.

If you mean mass murder -
Mao Zedong is generally considered to have been directly or indirectly responsible for the death of between 10-14 million people after WWII.

Most people say that Stalin's overall body count was closer to 20 million.

Are you suggesting that the US should have started wars with China and Russia to stop that slaughter?