1. Humanism facilitates ecological collapse.
Belief in the right of human supremacy over all other species (whether explicitly for domination or under the guise of stewardship) has brought us to the brink of an ecological collapse that will lead to a world of polluted wastelands and destroy most species on Earth, including the human species. Divorcing ourselves from values of aliveness, wildness, and regeneration has achieved disastrous consequences for the majority of the human species as well as all other species on Earth and all known habitats.
2. Humanism furthers alienation.
Belief in human separation from "nature" has forced us into a roles that foster neuroses and madness; an alienated existence inflicts increasing psychological and spiritual harm to we who live and more and more in a sterile, deadened, mechanical, symbolic world of control.
3. Humanism believes in speciesist Dominion.
The social construct of property arises from a humanist perspective that treats other species and landbases only as utilitarian to certain humans rather than possessing even the most rudimentary levels of intrinsic worth (spirituality), self-ownership (philosophy), consideration for ecological contribution (functionalism), or belief that they have no superior or subordinate value (nihilism/egoism).
4. Humanism rationalizes abuse.
To do this humanists arbitrarily elevate some measure (e.g. intellect, rationality, tool use) or content (e.g. soul, nervous system) to justify authoritarian behavior toward anyone classified as external. Such criteria change to rationalize the desire for authoritarian behavior as desired. Humanism makes excuses and rationalizations for human behaviors toward other species (slavery, extermination) that humanists would never concede to other entities (e.g. aliens or machines) with greater of even the agreed-upon measures or contents. It's an identity defense system, not a moral truth.
5. Humanism speaks the Myth of Progress.
Humanists almost always believe in the Myth of Progress, the belief that the state of humanity is always positively improving socially or technologically in a straight, forward, unidirectional line toward utopia, or at least claim this pattern has occured so far with the development of the Neolithic Revolution. Humanists believe that no other species does this, that humans are the subject and consciousness of the cosmos, and therefore everyone and everything else is an resource to exploit.
6. Humanism acts as the modern religious authority.
Humanism replaces God at the throne of authority with a particular and unquestioned image of the human species (the rational, productive man), and creates a new clerical class of scientists, technicians, bureaucrats, and others that mediate and divvy out "Progress".
7. Humanism has racist, colonialist mythology & history.
Humanism has constructed myths of an external "environment" and demonizes a concept of "nature" that it perceives as hostile to human aims.
Humanism therefore has easily accommodated racism, as it is anti-"nature" and therefore to some extent anti-any-ethnicity-that-resembles-"nature", such as "savages", "witches", "barbarians", "cavemen", "Indians", "Negroes", and supported those who embody a struggle against "nature", such as "pilgrims", "pioneers", "mountain men", Victorian-era masculine hetero males, Western scientists, who just happened to also be the colonizers.
8. Humanism hates wildness.
Humanists usually love the features of urban society that biotically cleanse landscapes to replace them with monuments to the greatness of Man and and testaments to the glory of Industry, artifacts of repression.
9. Humanism hates aliveness.
Humanists usually posses an intense attachment to mass society and technophilia and drawdown of non-renewables, and false notions that "Everything is natural" or "That which is natural is subordinate", and "Technology is neutral". On a spectrum of (a) all lifeforms and landbases have value, to (b) only humans and their settlements and artifacts and symbols have value, to (c) only industrial technology has value, humanists are a lot closer to (c) than they'd like to admit, and have justified or rationalized the eradication or subjugation of "backward" peoples and entire species or habitats for increasing technical complexity (see: Marxists, transhumanists). For the most part, humanists today can more easily come to terms with having no more traditional indigenous people on Earth, no more migratory songbirds on Earth, no more old growth forests on Earth, than having no more computers on Earth.
10. Humanism inherits ignorance & arrogance.
Humanist rhetoricians therefore often just cloak colonialism and dominion, taking them for granted or applauding them without giving room to radical critiques of their origins, histories, and trajectories, and in fact suppressing dissidents historically.
11. Humanism acts as another concept of sacrifice for control.
Stirner: "How is it with mankind, whose cause we are to make our own? Is its cause that of another, and does mankind serve a higher cause? No, mankind looks only at itself, mankind will promote the interests of mankind only, mankind is its own cause. That it may develop, it causes nations and individuals to wear themselves out in its service, and, when they have accomplished what mankind needs, it throws them on the dung-heap of history in gratitude."
12. Humanism has a cold heart.
Some anarchists have trouble confining our opposition to slavery and extermination to just 1 in 8,700,000 species, during a mass extinction no less.