To me, morality depends entirely on what one's most basic, fundamental drive is. There is no real mystical or religious significance to it. Ultimately every action we take, whether good or bad, is fundamentally in our own best interests, at least in our own minds. Survival is what drives the vast majority of living beings, humans included, and all the rules, morals and ethics we've built up are just very complex versions of the kind of rules that exist in a pack of wolves or a troupe of gorillas or a herd of zebra. We're social animals, and we follow the rules of our group, the "society/tribe/pack" or whatever, because we believe we derive some benefit from it. We value the security, safety and opportunity that being part of a group gives us, so we act towards sustaining the group. We are taught the rules and conventions of the group as we grow up, and we pretty-much apply them without thought, going through our lives pretty-much ignorant, unaware and entirely reactive.
The problem comes in when individuals in the group feel that their interests are no longer served, either by being part of the group, or by the rules that govern the group. If you are not benefitting from the group you are a part of, what possible reason do you have to maintain it and follow its rules?
So somebody who is homeless, jobless, lacks education, is marginalised, and feels alienated from society - who can blame that person if si starts undermining that society through crime, protest, sabotage etc?
That is the point I think modern society misses, especially in the West. We benefit from a stable society, but a society is only stable when ALL of its members feel invested in that society. If they don't, they'll try to create a different society, which means destroying the present one. That is why social security and social programs, public education, etc, are important. The society invests in the individuals, and in turn those individuals become invested in the society. Actions that keep the society coherent and homogeneous (there is strength in sameness) are "good", while actions that deviate are "evil".
At the root of it though, it's all still just our instinct for survival informed by whatever information we've collected.
I don't believe though that Survival is the only driver. Once your basic survival needs are met, and for some individuals even before that, Choice becomes the primary motivator. Take us for example. Because of the circumstance of Gender Dysphoria, we are willing to break with society, place our financial and social security in jeopardy, even risk our lives on HRT and in surgery because we choose to be true to ourselves. We move from being reactive to being active, taking control and direction of where we want to go, no matter the possible cost. More often than not, Individual Choice seemingly stands at odds with Group Survival, which is why we get labelled as evil, deviants, or just whacked.
The important thing to remember about Choice though, is that, if you restrict the choices of other people, you threaten your own freedom to choose. Self Determination is a basic need, and the moment you restrict that, you again disinvest people from the society. If they feel that they are not allowed to be true to themselves, to choose the things that are important to them, why would they want to preserve that society? Under this drive then, actions that promote Choice, your own AS WELL as that of others, is morally good. Choices you make that impact on what choices others can make is "evil".
At the end of the day though it's still a selfish thing though. I realise that a society that protects the rights and choices of others is more likely to protect mine, so I work actively towards that goal.
Compassion, I would argue, is a third driver distinct from either of the other two. You could remove compassion entirely from an argument for social welfare, or giving to charity, or protecting minority rights, and motivate them on the basis of either Survival or Choice. But when people give up their own lives in service of others, or are willing to die to save a stranger, or whatever - that is something different, something more. It's a need to give, to serve, that seemingly stands at odds with the basic needs of survival and choice, one that is not so easy to point to.
So yeah, sorry I rambled. Basically though, to me, laws, ethics, morals, cultural conventions - all of them ... at the end of the day there is no easy way to distinguish between what is "right" and what is "wrong". You might have one society where polygamy is practised, and makes sense, and another where mating with a single partner for life is the only acceptable, sensible choice. Likewise with the death penalty, or with abortion, or with whatever else. At the end of the day the Survival bunch will stand on one side of the argument, the Choice people on the other, and both sides could ( not do

) make convincing arguments to support their stance.
~Simone.