You can't just hack a toon into the game.
Can you show a screenshot of an account that shows damage for a simmed raid? I haven't seen a profile that has simmed raids, so I'm honestly not sure on that. You are correct it will show a blank for a raid they didn't do damage in.
As an aside, .gg is only showing raid history going back to Nov for myself and others.
It could have been leeching off a few different guilds and they were doing sims of lower tier raids. You only need raid currency 1 to unlock GK, which all raids provide.
It's the holiday season, so not many people in the office, also they tend to do a ban wave, instead of individual bans.