It's entirely up to to a user if they want to include banned users, but they shouldn't be surprised if others exclude them for putting banned or red trusted users on DT2.
Agreed, they should just bear in mind that doing that is essentially saying: "I believe the ban decision was not accurate, this person's judgement deserves to continue to
influence the reputation system in the forum" in the current system, and I'm sure most guys were not aware of that in the Turkish section...
I've just made a thread on the local section also quoting your good advice by the way:
https://bitcointalk.org/index.php?topic=5178202.msg52241677#msg52241677