Many people blame ego for all the wrong and suffering in the world. They are wrong.
First, there are many things without ego that suffer. Animals, small children and senile old people do not have an ego; and yet all of them suffer.
Secondly, ego is not the only source of wrong and suffering. Some bad things that happen are nobody's fault. As for manmade wrong and suffering, it can come from any number of places. Jeffrey Dahmer did not eat people for ego; he ate people because he enjoyed eating people. The Muslims who slaughtered 100 million people in India and Middle East did not do what they did for ego; they did it for Islam. The worst atrocities in the world were not done for ego. They were done for religions and ideologies that took a hostile view of the individual's ego and wanted to either destroy it or to subvert it to the will of the collective.
Further, ego is not always bad. Sometimes it can be an excellent motivator and drive people toward all sorts of accomplishment. This means that we owe a lot to ego, including most of our conveniences and freedoms. At other times it can form a bulwark against tyranny, as Ayn Rand has argued effectively. Affirming the legitimate prerogatives of the individual is a rightful course of action in face of such things.
The people who impugn ego also often impugn desire and claim that it too is a universal source of suffering. This is even easier to refute. There was much more suffering in Afghanistan under the Taliban, that forbade most forms of desire, than in Sweden or France, where desire is allowed. The worst suffering has been in places that take a negative view of desire. As for desire, it is not always a bad thing, and I see nothing wrong with desire for peace, comfort, companionship or even sex with someone you love.
The people who have the aforementioned beliefs also tend to extol positive thinking and say that any kind of negativity is something wrong with you. This is dead wrong. Real problems will not be solved by positive thinking. They will be solved by conceptualizing and implementing real solutions. Positive thinking will not solve the global warming. Positive thinking will not solve the gender war. Probably the only things that positive thinking can do is improve your disposition and make you more attractive to other people. That works if you are a salesman; it does not work if you are an engineer or a scientist.
If Christianity is right and the source of evil is Satan, then we would expect evil to manifest in all sorts of ways. They would especially include paths from which one would never expect evil. Satan would be unlikely to do wrong in ways that you would expect him to do wrong, but rather in ways that are completely unexpected.
One of such unexpected sources of wrong will be the heart. Many people think that the heart is inerrant or wise, but in fact heart can err just as much as can anything else. I have known any number of good people whose hearts lead them into negative situations. People were taking advantage of their compassion, or conning them, or guilt-tripping them into doing wrong things. Nobody would expect evil to come from the heart; but it very well can come from the heart.
Another such unexpected source of wrong will be logic or reason. Any number of people think that logic and reason are the solution to everything; but they can err very badly as well. There have been all sorts of theories in the academia that were later disproven. A man coming from the position of reason or logic may decide that feelings are a lower function or that religion and spirituality are for loonies. This will lead him to become a jerk and a bigot. I have of course seen this behavior all the time.
Evil can also come from another unexpected source: Survival and status concern. These can motivate people to plunder the planet and treat other people like dirt. I have seen even the kindest people acting like jerks when they were in the survival and status mode. Nobody would dare to impugn these considerations. Unfortunately they can be just as wrongful as anything else.
In short, there is no single source of evil within people. Anything within people is capable of both rightful and wrongful outcomes. Do not extol any function and do not demonize any function. Become conversant in all of them. And then arrive at greater wisdom and greater goodness than through any function working alone.