your own reply proves my point. you cannot say that women's rights have "improved" or that selfishness has "worsened" while simultaneously claiming morality is not objective. those words "improved" and "worsened" are moral judgments that require an objective standard to be meaningful. without an objective morality, all you have are personal preferences.
every instance of you saying "morality" should be replaced with "preference". I "prefer" my wife doesn't cheat on me, but it's not morally wrong... if it happens she didn't actually do anything bad. I "prefer" my child lives a good life, but if someone kidnaps them it's not morally wrong just not my preference and they didn't actually do anything bad.
the fact that people can be convinced of a lie about a moral issue doesn't make morality itself relative. the lie is still a lie, even if everyone believes it. you're right that our perceptions are fluid, but that doesn't mean the moral truth is.
simply because I feel one way about a subject and you feel the opposite way doesn't men we are both equally correct, this doesn't logically follow.
I can explain my perception and argue for it. For example, I feel that women’s rights have improved because they are now allowed to vote, study, earn money, and choose their partners. You might feel completely different, perhaps believing that these changes have harmed the traditional family structure you value. You’d hope there were an objective standard, but there isn’t. It’s just us observing reality and interpreting it within our personal limitations.
What you call “moral truth” often refers to topics where a large group of people shares an almost uniform perception, which then often gets reflected in laws. Take killing, for example. We have an evolutionary instinct to see killing as bad. Likely because this feeling helped us survive as a group. Since almost everyone feels the same way, it seems like a moral truth. But as thinking beings, we can challenge even this under certain circumstances.
For instance, if a person carrying a deadly, fast spreading virus enters a large crowd, the moral imperative to save hundreds might override the moral prohibition against killing.
In the end, it’s just us as a group, community, or species defining what’s right and wrong. Sometimes our perception is uniform, and you get to apply your moral truth. Other times, it’s split 50:50.