Socrates was a philosopher of a slave society. His remark, “He who is not contented with what he has, would not be contented with what he would like to have,” looks designed to convince the oppressed and the impoverished to be content with what they have so that they do not try to change the social order.
All slogans that have at their core the claim that people should be content and free in their minds despite being workers and slaves in objective reality are ideological pronouncements the intention of which is to reproduce the system of capitalism and slavery. But the oppressed and impoverished are discontent not because they suffer from some personality flaw that makes them restless, but because the conditions of existence they experience are such that they properly lead them to discontentment.
What the responsible and moral person does—that is, the person concerned with social justice—is instruct the oppressed to never been satisfied with the exploitation and oppression of their persons and the persons of their family and comrades and to rebel against those conditions and transform society in order to overcome them.