I believe that the word was coined by the Russian novelist Turgenev. He used it to refer to the idea that human values have no justification, and particularly to the idea that there is no justification for morality. He attributed that view to some of the young radicals in his time in Czarist Russia.
Many theists associated the idea with atheism -- moral values come from God, atheists believe there is no God, so atheists must believe that anything goes. I suspect that some of the more radical 19'th century atheists perhaps did think that.
There does seem to be a hint of that in this thread. Even if we don't associate it with moral values and with conventional ideas of God, there's still an idea that there needs to be... something... fundamental to the entire universe that gives meaning to our individual lives and provides direction about how best to conduct those lives.
The non-controversial fact of the matter seems to be that it is not the case that just anything goes. For example, all other things remaining the same, rocks don't fall up, and living according to your (current) values won't necessarily make you happy (this is in reference to a popular idea that if you live by your values, you'll be happy).
Traditional Buddhist ethics as exemplified in the Five Precepts are sometimes understood in an objective, absolute sense: that killing, lying, stealing, having illicit sex and taking intoxicants are never skillful, that they always result in suffering.
The idea is that
there is a regularity to the dhammas - and that thus, not just anything goes. That we cannot decide what result a particular action will have.
Relativists would like us to believe that anything goes, and that basically, it is up to us to decide what result an action will have - e.g. as if it would be up to us to decide whether killing someone will cause suffering or not, or that it is up to you whether you will enjoy coffee or not.
But apparently, reality doesn't work like that.
If there is a regularity to the dhammas, then we can also say that there is "something fundamental to the entire universe that gives meaning to our individual lives and provides direction about how best to conduct those lives."
We might not know how exactly those regularities work out, but for our actions to be purposeful, we have to assume that such a regularity exists. Otherwise, we end up in some kind of chaotism.