Do we have a moral imperative to think critically? According to me, absolutely. Is it ever possible to think through your actions free of emotional bias, and therefore think completely critical? Absolutely not.
To me (now this is based mostly on experience with fiction, so take it with a grain of salt), it seems that most of the awful things in the world (wars, genocides, crusades) come from a simple inability on the part of humans to see another point of view. We grow up learning to think one way, and once people challenge that way of thinking, or introduce their own, slightly different point of view, we immediately label that point of view as wrong. If the conflict is big enough, we have an emotional response - we get angry, or right away start thinking of them as bad people. We don't think about what the situation looks like to them, only to us. For most simple interpersonal conflicts, things could easily be solved by thinking critically about our emotional response, and what the conflict could mean to the other person.
What about when things get bigger? I'm talking about massive movements here, things like the Holocaust or the KKK. Are the German citizens who were just swept up in Hitler's propaganda just as implicit in the resulting genocide as Hitler himself? They were simply following what the propaganda and their neighbors were saying, but as a result millions of people were killed. If they had thought critically about what they were being told about the Jewish people, could the Holocaust have happened? Would they have been able to avoid jumping on the bandwagon if they knew what that bandwagon would have caused?
What about a more modern example? Same-sex marriage was recently legalized in the US, and people are opposing it. Violently. Clerks are denying gay couples marriage licenses, and are being hailed as heroes. They've been taught that their bible prevents this - they call it a sin. Are they thinking critically about how this affects the couples they're denying rights to? Could all the resulting misery be avoided if they took a minute to consider the deeper implications of the bible's statements on love, and the feelings of these couples?
I think that the kind of anger that causes violent feelings against another person is blind, and could be avoided if people really thought through the other person's feelings. In this case, there's definitely a moral imperative to think critically about the hate people perpetuate. In other cases hoewevr, this question could be approached very differently.
