To be fair I don't think its coming from training college (or, the crew concerned are misunderstanding the explanation of reporting) because a few weeks ago we were discussing this kind of scenario and they emphatically told us that if we are going to report something serious (for example, the situation Seja mentioned) that as a courtesy we should first inform the seniors who were on the flight that we wish to report x for reason Y, and allow them a chance to respond/fix. And only then if we are not satisfied that they have listened to the feedback to lodge a report- but still to tell them (except in the case of confidential reporting of course for safety issues)
I reckon it's an attitude thing, and down to the type of person they are in the first place, rather than something which is being encouraged...