What we see in practice is a lot of what goes on is contrary to the Law of God but people have ways of excusing it by finding some verse that they say is ambiguous and making a explanation that contradicts the plain meaning of the text. The reason is people are attracted to the ugly and profane and sexual sin and what to hear that it is OK and Kosher and so find some verse to support them.
It seems that Saul was in fact interpreting the word of God. It was not the same as simple disobedience.
If you look at the actual verses it seems Saul thought he had obeyed the word of God because that is how he interpreted it. I was not simple disobedience. It was first interpret and then imagine that he fulfilled it.
I would like to name this sin, "the sin of interpretation." חטאת הפירוש