You were suspended because you were part of the RMT chain. You hadn't just come into contact with RMT gil, you were actually suspected of either being a seller or a buyer. You stunk of RMT activity. Once they realized that you weren't actively participating in the RMT chain, they couldn't just leave the gil you made there. Because you were suspended you had to have been more "infected" with their gil than other people, or else you wouldn't' have been suspected at all. Rather than permanently ban your account, they modified the account and cleaned up the gil from it. Leaving your retainers alone and just hacking off the gil on your person.

I don't believe for a second that they used a robot in investigating the accounts. You can bump this thread and be upset, fine, but it could have been a lot worse. They could have just said, "Take all the gear and roll back the character." OR just banhammered you.