groupthink

Groupthink members see themselves as part of an in-group working against an outgroup opposed to their goals. You can tell if a group suffers from groupthink if it:

1. Overestimates its invulnerability or high moral stance,
2. Collectively rationalizes the decisions it makes,
3. Demonizes or stereotypes outgroups and their leaders,
4. Has a culture of uniformity where individuals censor themselves and others so that the facade of group unanimity is maintained, and
5. Contains members who take it upon themselves to protect the group leader by keeping information, theirs or other group members', from the leader.

...taken from this article by the author of Ender's Game, whose novels i love but whose opinion pieces i'm not always impressed by