Because no one knows anything whatsoever about actual anarchist political theory.

Largely due to it being heavily suppressed and propagandized against by States, capitalist or ‘Communist’, and their adherents.

Anarchy as thought of by the wide and vast majority of people is simply a state of chaos and violence with no clear rulers.

What Anarchy actually is is fairly simple.

Root words derive from Greek.

An- Prefix: Without

Archon: Tyrant/Cruel and Ruthless Ruler/Undefiable Authority

Non insane Anarchists are always critics of the state, corporate structures of organizing the work place, most forms of organized religion, oppressive social norms and anything that creates and maintains any kind of hierarchy in society that results in oppression, impoverishment or cruelty to any particular group of people for illegitimate reasons.

Anarchy is essentially very similar in many ways to communism as Marx envisioned it, in that it is an idealized, as yet not perfectly defined goal of a just, egalitarian and democratic society that heavily emphasizes people being adequately represented economically in their daily lives as workers, as opposed to the standard liberal capitalist model where your boss essentially has authoritarian power over you in the workplace.

Both Marxism and Anarchism are highly critical of the profit motive and the ability of a very small number of people to own all or much of the capital (means of production such as factories) of a society, for very lengthy and detailed reasons.

A very common misunderstanding is what is truly meant by ‘private property’: most people unfamiliar with Marxism or Anarchism believe that Marxists and Anarchists believe that no one should be allowed to singly, individually own /anything/.

This is false. While many different adherents have different precise definitions, generally speaking private possessions are just fine until they get to the point of owning something directly and singly that has a massive impact on the lives of others should you choose to unilateraly use your ‘property rights’ in a way that is beneficial to you personally, but harmful to a large number of other people.

Further, Marxists and Anarchists both generally agree that ‘property rights’ as we currently conceive of them really only functionally exist for the rich and powerful, and are enforced via the power of the state.

Anarchism significantly differs from many later Marxist derived theories such as Leninism, Stalinism and Maoism that generally emphasize that in order to actually achieve an ideal, non capitalist society, one must create a massive state structure (or subvert an existing one) and place all power to reorganize a capitalist economy into a class of totalitarian economic organizers and planners, and that during this process the state is entirely justified in basically any means of crushing dissent it deems necessary.

This is of course heinous to Anarchists, who view a totalitarian state as essentially criminal.

What modern Anarchists, who are, again, not insane, usually support are working both within and outside of existing norms and government structures to meaningfully improve peoples lives amd expand their rights:

Mutual Aid: Direct Involvement in you local community to feed the hungry, house the unhoused, provide aid to the sick and displaced.

Advocacy: Doing what you can to promote ideas and views that will be beneficial to the masses, or to protect at risk minorities, both within existing formal societal structures like governments and businesses, and also within society generally.

Many modern Anarchists are also very concerned about the power if states and corporations to abuse the environment and curtail freedom of expression.

Anarchy also has another useful definition in the context of a world of nation-states:

Anarchy is that same common understanding of a world without rules and chaos, but the realization that this simply describes our current world given the history of actions of and between nation states, who often engage in many harmful acts against other nation-states and their populations, and rarely actually follow any rules or norms which are supposed, but i actuality rarely do, govern affairs between states. States will often do whatever they believe they can get away with that will benefit themselves, even if it means massively harming another state or group of people.

Finally, if you want to also be a modern technologically savvy anarchist, aka a cyberpunk, you can realize that the advent of computer and digital technology means there no longer exist any actually valid reasons, in very many cases, to actually pay for software, and that you should be an advocate of open source software.

So, in summary, Anarchy is not a state of chaos, without rules.

It is a very complex and nuanced political theory of advocacy for a more equitable and more just society.

No serious Anarchist believes that the world would be better if everyone was free to rum around and do literally whatever they want on an individual scale.

What exact kind of society do they propose?

Well unfortunately that differs wildly from Anarchist to Anarchist, but again, as with how Marxist socialism is but a /process/ of transforming from a capitalist society into an as of yet not perfectly defined communism, Anarchism is a /process/ and /method of analysis/ of how to transform into a better society for everyone.