Yes, because these are extrajudicial killings with high death tolls and serious injuries for bystanders.

Suppose China, Russia, or the EU would conduct drone strikes on US soil but only target evil people such as Donald Rumsfeld, who is known to have ordered torture and initiated a war under false pretense. However, many bystanders including women and children would be killed as well. Would you be against it?

I would be against that, no doubt about it.