Rules come from somewhere.

That somewhere is rulers.

Therefore, no rulers => no rules.

Therefore, (Anarchy => no rulers) => (Anarchy => no rules).

Well, rules in anarchy have to come from consensus of the people. So the only rules, in practice, are those that the people are willing and able to enforce against those who wish to break them.

History shows that, in anarchy situations, those who wish to break the rules are sometimes highly motivated and well armed. Thus anarchy at least means "no rules that apply to a warlord when he really wants them not to".

Now, one could argue that that is essentially the situation with the US government now. But the well-armed warlords tend to show considerably less restraint than the US government does.

There is no such thing consensus of the people in any communities of nontrivial size.

In anarchy situations, whoever is capable of filling the power vacuum creates new rules - the "highly motivated and well armed" groups don't break the rules (since if they disagree, there's obviously not a consensus about those rules); they define the rules and others possibly break them.

True enough. But, technically, once someone fills the power vacuum, it's not anarchy any longer.

(But if you're living in it, that "technically" isn't going to comfort you one bit...)

Rulers can certainly provide rules and conventions. But that is not the only, or best, place they can come from. Rules are usually emergent, and these kinds of rules are better suited to the communities they arise in, since they are tailor-made for the circumstances and preferences of the people from which they emerge. Contrast this with Federal rules and regulations which have little or nothing to do with the way life is lived in rural Alaska. But this is the same old argument about the failures of central planning that has been ignored by progressives and conservatives for more than a century.

See: English common law prior to being co-opted by the state.

Also see: David Graeber, anarchist, https://www.youtube.com/watch?v=PVDkkOAOtV0

People who think like this suffer from a lack of imagination, in my opinion. They are people who cannot imagine that others can negotiate or have negative experiences of being ruled over, thus must be dictated to.