Where do you draw the line? Would you allow Joseph Stalin to coinjoin his Bitcoin to disguise the shares of loot paid out to his underling politicians, cops, and soldiers? Or would you perform the necessary step to hide these monsters in the shadows to allow them to blend in with their victims?
The protocol doesn't care and is not supposed to care who uses the coins, why, and when. That's the beauty of Bitcoin that you and your buddies are voluntarily limiting. Bitcoin works without the intervention from corrupt agencies who would like to control it and decide what is acceptable and what not according to their agendas. Anyone that works with them and helps in that control, stands on the wrong side.
Have you considered that the honest users in the coinjoin transaction you coordinate don't want Stalin, SBF, or Chainanalysis to participate either? What if honest users refuse to sign any coinjoin round containing Stalin's coins, will you ban the honest users from participating in order to ensure Stalin gets to hide his loot from slaughter and slavery?
They aren't supposed to know about each other and any other coinjoin participant. If Mark, Bob, Sara, and Tom don't want to participate in the same coinjoin because they know Stalin is there, or your analysis partners found or told them he is there, something is seriously wrong with your approach.