First let me define terms as I use them, to minimize confusion as to what I'm saying. I'm not saying my use of terminology is "right" (which is a different discussion), I'm just trying to optimize our accurate communication.

My understanding is "morality" or "morals" has to do with personal (individual) codes that we use to guide our personal decision making and thus behavior. While "ethical" or "ethics" is a set of standards that a community possesses (either intentionally or not) that are a set of social norms that may or may not guide behavior, though those who violate them risk negative consequences from the community. "Legal", of course is a subset of "ethics" that is codified and enforced, formally. All of this is technically separate from "right", which unlike all of the above subjective terms, is objective.

Okay. Now to your questions/responses. By my use of terms, what makes an action immoral, is whether or not an observer (whether a first person actor or a third person observer) finds the action in violation of their set of moral codes. Obviously this can lead to what we commonly observe, which is disagreement between observers. Which is expected since we're dealing with a subjective question. My comment about the "majority" was addressing what I call ethical (as opposed to moral), since I thought you were addressing community standards. As pertains to communities, yes the majority opinion constitutes the standard. Sounds like you're conflating "moral" with "right", since you used the slavery example. By my understanding, slavery was acceptable behavior in the community of the antebellum South, thus it WAS ethical, yet it is currently unethical in modern society. This is a description, not a judgment. Of course two individuals can debate whether or not slavery is "right", but that is problematic, since as an objective descriptor opinions should be excluded from the conversation.

As to the role of universality, it is required in objective measures, but it's presence is not proof of objectivity, since some subjective entities are tremendously popular.

I agree that different communities (as a group) makes different subjective trade offs as the source of their differing ethical standards. That is the core of the issue. Folks like to use murder as a convenient example to illustrate their points, but it is a poor one since it is that outlier example I referenced above, namely an extremely popular (to the point of near universality), yet subjective opinion, thus mimicking objectivity.
This is interesting. Morals are personal; ethics are the same thing, but tribal. This changes everything, I think?

The question in the topic title intends (I think - I've been wrong before, though) to ask what makes an action (morally) wrong, although in your terms, I should probably say "(morally and/or ethically) wrong".

As it is, and retaining your terms, the topic title literally asks what makes an action unacceptable, according to the personal behaviour code of a single (unspecified) person.

My understanding is that morals are internal (to the individual), while ethics are external (from the community). Some like to describe ethics as objective, since they can be described statistically, that is, by quantifying the different individual (subjective) opinions to define the community's majority opinion. Sort of like saying that while my preference for chocolate ice cream is subjective, saying 60% of the community prefers it is an objective measure. To my mind, that is an incorrect conclusion. Since one could say that in the community of "me", 100% prefer chocolate. This does not magically transform my subjective preference for it into an objective measure. It's still subjective.

As to discussions on this or that being "immoral", most use that term interchangeably with "wrong". Which since (to me) morals are subjective (while wrong is objective), is internally illogical and thus nonsensical, since moral is descriptive while right is judgemental. For example if I say that I find assisted suicide to be immoral, are you learning about me (and my mindset), or are you learning more about assisted suicide?

Statistics: Posted by LuckyR — 24 minutes ago