It's simple, the timing of these posts is suspicious. I have no 40k knowledge, so I don't know what my "flavor" means. However, my PM clearly tells me that I'm town (because blue, for one) and that the IRS (red, so bad guys) are "heretik invaders". Obviously, I see absolutely no way to get confused, even if my flavor were questionable from a lore standpoint. A monkey would be able to figure it out.
We have no new mafia players this time, so clearly the train of thought goes to "why would shade feel the need to clarify in response to the GM's post". The result is that Shade isn't town.