Where is it stated that DT1 members are not allowed to discuss the actions of other DT1 members? Why are individuals not allowed to try to sway the opinion of other individuals?
On the contrary, it is actively encouraged:
So if someone on DT1 is doing something stupid, you can ask other DT1 members to distrust them.
As far as I can see, eddie13 has taken completely appropriate action by airing his grievances out in the open and giving mosprognoz a chance to address them, when he could have equally just bypassed mosprognoz altogether and directly PMed the users who are including him (as theymos himself has done in the past). I would expect someone on DT1 to at least be mature enough to address these concerns in an adult manner.