@Billet1500 4x4 and
@Mason1217 Perhaps this is true for some tailgate cables and folks can try your test, but your explanation is not true in all cases... Something is absolutely wrong with some tailgate mounts/cable lengths.
For instance I do not have the assist strut and the left cable is slack. Others have said their right cable is slack. When I put weight on my tailgate (no dampener strut) the right is tight, but the left is still slack and it absolutely won’t take on a load unless I twist the tailgate itself... which I don’t want to do lest it bend and not close or bend out of visual alignment.