It's not complying if you resign. Difference is whether you're replaced after refusing to kill people or before - but you'll be replaced and the next guy will kill people regardless. If you quit before as a high profile individual, you can signal that something is off. If you don't quit, you may get martyr'd. Which I think most people don't want, especially anyone with family.

Worse, an insider reports that the generals were all monitored for signs of discomfort and disapproval during the speech. They're being watched. Anyone not loyal to Trump first and foremost, is going out. Anyone who actually disobeys orders may or may not find their family deported to South America, Africa, whereever, as terrorists. I suspect some of these generals are currently more afraid for their families than you are.