A PRIORI: God is perfect and unchanging.

Conservative Evangelicalism is of all things the Most Logical.

Creator God knew before He made humanity what humanity would be like.  He knew male and female before he brought Adam and Eve,  real flesh and blood humans, into existence.  There are not a lot of Adams and Eves, there were only the two and out of their relationship, all humanity exists.

They had only one "Thou shalt not"  only one.  They gave into their desire and humanity was broken from then on; would ultimately need a blood sacrifice for sinful man to be in a relationship with a holy and sinless God.  The blood sacrifice was God himself in A.D. 1.

The principles for Godly living have not changed in the millennia of humanity.

God, being most logical and just, over time gave us His Word, both in His Son and in the written Word.  He did not dictate it but His Spirit oversaw the ultimate creation;  from Genesis to the Revelation.

Because God is Perfect,  Scripture does not require an upgrade.  It said EXACTLY what God wanted it to say in the autographs.  We do not have the autographs but people underestimate the millions of hours theologians have put into making sure the very words of the autographs are truly with us.

It is totally illogical to think a perfect God needs to make an upgrade.

Conservative Evangelicals view life thru the prism of Scripture. It is the anchor that never changes; though sometimes our understanding may change.  BUT,  words have meaning.  As logical as it gets.  If Holy Scripture says, "Thou shalt not,"  then thou best not.  It's not going to change to God saying, I've changed my mind; go ahead.

Non conservative religionists view Scripture thru the prism of the current culture; which is the most illogical thing ever.  What is current today will be passé in a very few years; maybe tomorrow.  They are always denying the reality of "Thou shalt not."  For Non conservatives; this is dependent upon changing the obvious meaning of simple words.   That is illogical.