It is a common accusation against individualists that they believe in a "might makes right" mentality. Due to our refusal to believe in their collectivist ideal of supposed security and comfort, we are cruel, unfeeling people who wish nothing but for the weak and incapable to be crushed.
As for most collectivist arguments, this is pure projection. I have yet to meet one market anarchist or atheist who believes in "might makes right". Rather, it is statism and religion which promote a mentality of power over persuasion or reason. In fact, power as justification is inherent in both of their founding narratives. Statists believe that the state must have the power to dominate society in order to enforce a singular value system, and that the state is justified in its worst atrocities because it needs that power. The religious believe that God is justified in its worst atrocities and owns all human beings solely because it has the power to create and destroy life.
And if you think that's a straw man, listen to what Lee Strobel, probably THE most well-known name in Chrisian apologetics, has to say about it :
People assume that what's wrong for us is wrong for God. However, it's wrong for me to take your life, because I didn't make it and I don't own it. For example, it's wrong me to go into your yard and pull up your bushes, cut them down, kill them, transplant them, move them around. I can do that in my yard, because I own the bushes in my yard.
Lee Strobel, The Case for Faith, chapter 4
Both statism and religion are based on belief - belief that government is necessary, and belief in the existence of God. And belief precludes the possibility of persuasion. Persuasion is only possible when we have objective facts to show and explain to the other person. Insofar as belief precludes persuasion, the only way to impart belief is by force - mental (childhood brainwashing, for example) or physical (beating up people who believe otherwise).
The moral premises for both the state and religion are also cut of the same cloth. Statists believe either that singular power makes right (monarchy), that majority power makes right (democracy), that the "common good", as chosen by the ruling class, makes right (fascism), or that "class" power makes right (communism). In no case is there any consideration for the truth. Same for the religious, who believe that whatever God wants is moral, regardless of reality.
Belief in the state and belief in God are predicated on the same premise: that there are some beings that are inherently superior to us in the social order due to their might, and can dictate morality to the rest. There is absolutely no reason for us to consider "God's law" or the "state's law" as anything but an arbitrary construct designed to pursue a specific set of ruling class values (those of the Church and those of the state). They are followed, not because people judge them good, but because of "might".
Look at who rejoices in violence and brutality. Surely the Christian does, when he reads with enthusiasm the Old Testament stories of genocide, or when he rejoices in the future Hellish destination of some of us. Sure, they say that it's all for ends we cannot understand, and that God has his reasons, which is to say that they really believe these things out of their own dark, violent impulses and refuse to acknowledge it, so they pin it on their scapegoat. And surely the statists do, at least those who support state police, the prison system, and war. They always clamour for their "country" to have the most guns, the most bombs, the most planes, and they stand the tallest when they salute the flag. They sure are in love with "might".
In all considerations, one basic fact remains. Both anarchists and atheists desire to free people from collectivist coercion, and to live in a society where people express their personal values. Statists share the religious desire to enforce submission to their collectivist ideals, through force of arms, mental threats, and social engineering. If there are any screaming children, if there are people who believe that might makes right, it is they.