You could also NOT kill any Nazis in Wolfenstein 3D; you could just stay in your jail cell and not go anywhere. You're not GONNA, of course. Same principle.
Staying in your cell is hardly "playing the game". FO1 allows you to play the entire game without violence.
Again, doesn't matter. Apparently I wasn't clear enough about "the principle" when I stated examples, but the principle IS "possible is irrelevant to what's likely". During the early Bush days in the U.S., before 9/11, when government was trying to find ways to expand its reach but kept running up against that pesky Constitution thing, advisers to the President would bring forth plans that Bush felt weren't enough, but no matter how much he asked for possibilities to excuse further reach, they kept coming back with no excuses to do so, based on likely scenarios. So Bush finally asked them to come up with scenarios that were not LIKELY, but rather were POSSIBLE. They came back with all kinds of radical things that would allow lots more growth of government influence. But the people who had to run the numbers who setup the scenarios were very displeased with this method, and they pointed out, very appropriately, "Yeah, it's POSSIBLE that these countries might attack us, it's also POSSIBLE that a meteor would fall out of the sky. Possible doesn't really matter, but they're blowing it out of proportion to sound like it does." This, by the way, was the groundwork for that spectacularly useless "Star Wars" plan, for those wanting to look this up. Bush needed LOTS of support for continuing that fanciful project, and there were simply no precedents to suggest it had any use, so they had to conjur up equally fantastical scenarios to excuse the exorbitant expenses that the project would involve.
Long story short, cause I apparently MUST be as clear as fucking possible with you people, what's possible is of no consequence, here. Yeah, you COULD blah blah, but guess what, you're not. If ANY of you picked up FO1 for the first time ever, having never played anything else like it (cause let's be honest, there WAS nothing else like it, at the time) and you immediately went about trying to play the game non-violently, that would be astounding. But guess what, that just didn't happen. The likely scenario would be to approach the game the most directly. Fight breaks out, you fight. Travel must be undergone, you travel. Fight breaks out, you fight. So on and so on. It takes a greater appreciation of what the game offers to actually replay it subsequently and beat it without killing anyone. Same principle as approaching any other game, or any other ANYTHING. You will come at it the most likely direct manner possible. Only afterwards will you explore its greater possibilities.