Depends, what do you mean by defective and what do you mean by rebels?
I can see why you observe the ant colony thing, however I think we shouldn't mistake having a unified ego as having a unified controlling hive mind as ants do. Whether or not ants even have an ego is beyond our ken.
Lets bring it down a notch from a unified collective ego and just describe an ethical national egoism.
Now, how familiar are you with the writings of MLK jr? "I submit that an individual who breaks a law that conscience tells him is unjust, and who willingly accepts the penalty of imprisonment in order to arouse the conscience of the community over its injustice, is in reality expressing the highest respect for law."
Here we have an insight on two different interpretations of the law and how they relate to ethics. First, we have those who hold true the Rule of the Law. By this interpretation, all laws are ethical and to be followed without question. Then we have those who hold true to the Spirit of the Law. This interpretation comes with the belief (which is generally agreed upon in moral philosophy) That which is legal, is not always ethical, and that which is illegal, is not always unethical. So, even rebels can be deemed as moral agents. Without bad, how do you know what good is? Three examples: Rosa Parks illegally refusing to give up her seat for a white man. Was this wrong? Modern example: Man with a chronic illness self medicating with marijuana in a country it is illegal. Is this wrong? Timeless example: A family illegally emigrating to a country to escape war/violence/famine/prejudice and/or persecution. Is this wrong?
Are all criminals, merely that.. criminals? Or are some people moral agents who hold to the spirit of the law and wish to be part of the process for molding and shaping it into something a little bit better? I see moral philosophy as a collaborative effort. We are all molding the field of moral philosophy as we go and we are the models we are observing when we are deliberating on whether or not an action is wrong or not. From the seemingly virtuous person who may give us an insight on what it means to be good, to the morally despicable person who may give us an insight on what it means to be bad.
Now going back to the dialogical self, we also can view ourselves as having internal agents. A theme you will find in TV and Cinema is the Angel and Devil on your shoulder. This kind of simply describes how agents of a dialogical self interact within. Your inner monologue, can be interpreted as different agents of self, some of which have conflicting goals. For example, when a person goes skydiving it is not uncommon for a lot of internal conflict on the way up. Fear and survival instincts telling you to by no means jump out of a moving airplane and your need for thrill, adventure and excitement spurring you on, telling you to just jump. Finally the agent of rationality settles the dispute by reminding the decisive you that you are wearing two parachutes and are with professionals to help keep you safe.
Rounding back to OPs question. If these three different agents I've described, the individual ego, the national ego and the unified human ego are truly identifiable and we as humans have the ability to improve ourselves and contribute towards the collective, (which must also treat us with respect and allow for equal opportunity for all within a democratic society, without sacrificing people for the sake of a fictional higher class. So not fascism, never that) Then I still believe that ethical egoism when applied to the collective ego and even the national ego (so long as your nation doesn't achieve this by needlessly warring or enslaving other countries and peoples and seeks to cultivate outward friendship with other nations in service of the collective ego) can truly be ethical.
However, this is in an ideal world where people can agree on how to ground ethics in the first place.