It is the job of a modern soldier (be it Army, Marines, SEAL, etc) to concern himself with that. Have you not read up on the ROE? You're not thinking about the US mission in Iraq/Afghanistan clearly if you think his job is to just start wasting people indiscriminately. This isn't a Duke Nukem game. He could waste 1 innocent and create 10 militants in one fell swoop.
And I have the utmost respect for Patton. He's great in a conventional war where he was given open latitude but he could barely operate in a conventional war without significant problems. He'd have been a spectacular success and then a spectacular failure. General Mattis, a guy that is a total bulldog on the battlefield (just look up some of his other quotes) said this:
Iraq required restraint, patience and a respect for the people the US was trying to work with. Mattis would unleash hellfire and brimstone on terrorists and insurgents but he didn't lose sight of the primary objective and that is bringing the Iraqi people in line with the US mission in Iraq. But General Mattis probably had no idea what he was talking about, right?