Yeah, because the only faction in New Vegas is Caesar's Legion. Mr. House, The Boomers, Great Khans, NCR, Brotherhood of Steel and several other factions don't exist. And even then, a case can be made for the Caesar's Legion, which Caesar explains himself. There's also a ton of sidequests with morally grey areas in the first two games and New Vegas. You also didn't mentioned nothing from the first game, where a case can also be made for the Master. If you are gonna throw claims like that with no regard, at least back them up with actual ingame examples.