Asking if English is your first language isn’t an ad hom, if you spoke this well as a non-native speaker that’d be more impressive than misunderstanding it as a native speaker, but neither is wrong or whatever, you just misunderstood me and used it as the basis for claiming I lost all credibility, which was annoying, but not a huge deal as long as it’s cleared up now.
Objective truths require objective evidence
So I’ll start my thesis here, hopefully it’s not too abstract for you to follow when you’ve never engaged in this type of material before by your own admission.
Objective evidence exists only within the framework of certain axioms. When you take some simple evidence, let’s say an apple falling, how do you know it fell? You take it as an axiom that your senses are accurate in describing some material set of conditions that exist in an objective reality. Even the concept of an objective reality that is shared with other beings is an axiom we take. You could just as easily be in a simulation alone, with no other conscious beings around you. Reality could be constructed as you view it.
This could be true even without a simulation theory. You could be the sole conscious being in existence, and all of reality is a hallucination that you just believe has to have consistent objective truths, so that’s how it appears to you.
The point is, it’s not truly knowable what the true state of reality is without taking axioms (engaging in assumptions). Once you assume there’s a real, shared, persistent objective reality, and that your senses accurately depict this objective reality in an ontologically consistent way, then you can start building what we call objective truths.
Moral truths function literally identically to this. Without axioms, in both the descriptive and normative realm, nothing is knowable. Functionally that doesn’t work though, people take axioms unconsciously, and we can’t not take them. If this isn’t your first exposure to the idea of axioms, you’ll understand it’s generally regarded as better (or often even required) to only take axioms that are “self-evident”. That is to say, you don’t take an axiom that all matter in the universe is held up by invisible flying unicorns, but you would take the axiom that you exist in some ontologically consistent and shared space.
If you’re in a conversation with someone, and for some reason they take a different axiom than you (e.g some people take the axiom that God exists, which is honestly far too complex to be reasonable), then you can’t functionally communicate about the nature of your (supposedly) shared universe. So to have the conversation, the religious person has to drop the axiom to be able to discuss whether or not you’re able to arrive at the existence of God by building off other axioms that all humans share (hint: you’re not).
Normative discussions work this way too. Essentially all humans take it as an axiom that suffering is bad (there are exceptions in both the descriptive and normative case, e.g schizophrenia or sociopathy, where generally accepted axioms about the true nature of things are misaligned).
You can use logic and reason to build off descriptive and normative axioms, and some people do this incorrectly because they’re being irrational. Just because people disagree on these things doesn’t mean we throw out the idea of objective truth (descriptive or normative), it just means some people are going about understanding the true nature of reality wrong. Flat earthers and Islamic fundamentalists stoning gay people are both wrong in the same kind of way, they’re not using logic to build off proper axioms to try to find the true state of reality.