The level of vitriol is proportional to the harms. Ayn Rand's childish philosophy has adherents who have caused significant harm to society. Similarly, if Mein Kampf or Das Kapital had not gained a following, we might not have such vitriol for those books, and we might spend more time discussing if we see their archetypes in the world around us, but they did, and that discussion is rightly not as prominent as the criticism.