Ayn Rand has a problem with violence. I think that all anarcho-capitalist ideologies (of which Objectivism is certainly one) have the problem of violence.
To the extent that anarcho-capitalists defend violence, they do so for purposes of individual and collective self-defense. But that’s not what I’m talking about, here. I’m talking about aggression, particularly violence as an adjunct of theft. I’m talking about, quite literally, legalized banditry.