About a month ago there was a post on this topic.
I think that this distinction comes from people’s work with Nietzsche. Nietzsche had a critique of what he called the "slave moralities" that were typical of Judaism and Christianity in a particular historical context. His critique of resentment (often untranslated from the French ressentiment) seems central to this.
How does resentment work? Let’s take the case of Bobby.
Bobby experiences suffering. Because of the power relations in their context, Bobby does not act against the cause of their suffering. They seek out a cause for the suffering; someone to blame that is outside of themself.
That suffering goes into Bobby’s memory, and disposes Bobby to strike back at that cause they represent as the cause of their suffering. Imagining revenge, and having an imaginary revenge, against the perceived cause comes to replace attempts to strike back immediately against the harm, and that fantasy does help to deaden the pain of the memory.
Often, Bobby will tell their self, “I will strike back tomorrow!” – After judging the harmer as bad, Bobby concludes that Bobby must then be good. Indeed, that is the reason Bobby gives themself for why they are not actually impotent to enact their revenge; because they are good! Lack of action is seen not as impotence but as a choice to be morally good (e.g. by turning the other cheek). Grinning as one bears suffering becomes moral, and that morality spreads among those similarly oppressed.
This is why the idea of hell is so desirable to the resentful person – it is a place to play out the revenge fantasy in the most full way, to understand one's own suffering under oppression as good, despite how the oppressor continues to enjoy prosperity in their oppression. Now political power and nobility are seen by Bobby as signs of evilness and damnation, and Bobby’s revenge will be completed through God as proxy.
In this context, it would appear that moral values simply are signs of distress, impoverishment, and degeneration insofar as they arise from, and answer to, the painful malfunction of resentment.
In an anarchist framework, we can understand a problem with this in terms of a tendency against mediation of various kinds. The resentful person, the moralist, is obsessed with the perceived agent of their their suffering – including that agent’s values - and seeks to invert those values and claim that inversion as moral. But not only is their entire existence then framed by themselves as a reaction to their oppression, their values are built on the same ground as their oppressors and are mediated first through that oppression. They are reactive, rather than active.
I think here what people often call ‘ethics’ in distinction to ‘morality’ is the process of coming to hold active dispositions and to do active actions, whereas ‘morality’ is what Nietzsche called ‘slave morality’ – those ethical positions that make virtue out of reaction.