No one has been negative. Nor has anyone said that anyone should state “it’s not my job, guv”. People who do the job have simply pointed out that customer service isn’t a part of the driver role.
As for “intervening” when other staff do their jobs, how would you feel if a member of platform staff came and told you how to drive your train?
As for telling others to change their jobs. It sounds as though you go looking for interaction with passengers. If you crave it that much, maybe you should retrain as a guard?