I dont think spree killers think they can make a noticeable difference by just killing a few people. A single man cant make a difference, but he can do something and hope for others to join him and eventually all acts will add up and change will happen. He might not be able to make a difference in his lifetime, but everything a man does stays in this world and his actions will live on for future generations.
Men who just off themselves are pathetic and egoistic. They dont do anything beneficial for future generations, they wasted their lifes entirely. Self hate and self pity is cowardly and it is one reason why we suffer, because men in the past were cowardly and gave rights to women. We have to redirect our hate outwards.
My point is, while I highly advise against anyone from going ER, because it is such a horrifying act of anger and I would totally never want to see a STACY getting brutally ERed, VIOLENCE is really the only way to make a difference. All men who have made a difference historically have used violence. Mohammed, Hitler, even Jesus. Im not encouraging anyone to do anything harmful, but really you can hang outside in the sun all day, tossing a ball around, or you can do something that matters.