To say otherwise is to say that people on death row should never be acquitted because it was true they were a murderer at the time of the trial, and that truth is unchangeable.
(or to use an example from cinema, at one point it "wasn't true" that cigarettes were harmful)
[0] Because the assumption that the current society is somehow in possession of the truth is mistaken and has been shown to be mistaken again and again. Furthermore such an ideology would be just the opposite of what it means to live in an open society.
>We know no truth
So you're saying we have 100% certainty that we aren't capable of knowing anything is true with 100% certainty?
In some places abortions is accepted by law and society. In other places you get jailed for it. And it all was different a century back. Or child labor. Drunk driving.
How can there be one truth to those moral questions?
For example what is the truth about the morality of guns in ET movie? I still don't understand what you mean.
I think we should be better than “We can’t see anything objective to base our morality upon, so we’ll just base it upon our feelings.” mindset. We should be able to at least admit we don’t have a normative morality and our laws and law enforcement is simply bullying people and making them submit our (collective) feelings and desires because we have the power and means to do so.
Regarding the question what God says being subjective: No, there are arguments of current and past miracles, and recorded honesty, reliability and mental health of prophets, and many other things. At least for Islam. You can search. If you have questions, simply refer to this playlist [1]. Every question regarding Islam and modernity is (repeatedly) asked there.
I could write a lot more but I have a lot of things to do so I’ll simply direct you to this documentary series [2] which elaborates on morality among other things. Both playlists are intellectual gems no matter what your background is.
0: See Rabbis having authority and knowledge over God in Judaism, and countless versions of Bible which are clearly not all the exact words of God, and instead of non-prophet humans. Also Christianity and Judaism doesn’t see prophets as constantly checked and sinless. See examples of sins commited by prophets in Bible and Old Testament.
1: https://youtube.com/playlist?list=PLcnL9bB-q3ylQ9CZdB8YfjoDv...
2: https://youtube.com/playlist?list=PLcnL9bB-q3ymnRNcpZGcVVjiD...
I still don't understand how "guns in E.T." can be "the truth"