Account sellers may have purchased the account for resale and are not tied to the scam, but if an account scammed they fall into the collateral damage category as well. It's the account that gets ruined, the seller themselves may have nothing to do with the scam.
Again, it should be looked at as case by case, if the seller was not in control and didn't do the scam, why tag them? Aside from the fact that people dislike sellers. The account that the scam was done on is what should be tagged.
Its a whole mess of a topic for sure. My mind could be swayed and its a subject that we will never get 50%+ of the masses to agree on.