I don't think there's anything intrinsically unethical (or ethical) about self-citation. If your previous work is relevant, then it should be cited. If it isn't, then it shouldn't.
Morality and ethics are two different things. So it depends what your morale is. Its definitely not ethical to steal other person work. But you work hard and I can not see anything wrong with citing your own work in your own paper. If someone else wrote it before I would mention them as well though. Just last week I asked Mike the same question.
I think it is an ethical thing to do. It also keeps you out of trouble and sustains your reputation as a researcher. On the other hand, morals are a personal thing; we all have different morals and whether we employ ethical writing may be influenced by the morals that we have.
When a study or an article is published, it becomes the property and material for the academic discourse. That's why journals and other complication houses review the work of authors before publishing it. Therefore, anybody in the academic and research discourse who finds the work insightful and relevant to their study, they can use it, including the original author of the work. There's no moral or ethical issues around that.
It is moral right which means, you are citating the outcome of your hardwork in academic research. Generally, citations will be quoted to support the findings of our research work specifically in Social science and other areas.
When citing your own work, you should avoid gratuitous self-reference. The second thing to remember is that self-citations, when used, should sensibly contextualise your new publication. A common mistake is when a person discusses a well-researched phenomenon, but they only refer to their own work. https://achilleaskostoulas.com/2014/02/08/self-citation/
It depends. For example, I finished an experiment and published the data in paper #1. Now, I have a further study which based on my earlier findings (already published in paper #1). Then, when I publish a second paper, I have to cite the first paper (no choice). This should be very normal.
Self-citation may be necessary in many cases to complete the research study according to the world's progress. There may be a room for self-citation - but it is a good practice to limit the practice when possible. Therefore, self-citation is a sensitive issue.
On the other hand, "Citation Farms", also known as "Citation Cartels", consist of authors who routinely and enormously self-cite or cite each other for the purpose of raising their citation counters and, in turn, promoting the impact of their publications.
Let me show you this paragraph:
"Self citation. Researchers may need to cite their previously published works in order to communicate an idea effectively in their present manuscript. While IGI Global encourages the use of self citations in these cases, it is important that self-cited works do not account for, at most, 50% of the total references in the manuscript."