> Here Jesus is contrasting being righteous i.e. non-sinners with sinners.
There are no non-sinners, so this is not true. We know this for certain because Jesus was addressing the Pharisees, whom he clearly regarded as sinners (Mt. 23; Jn. 9.41).
> Your claims that Mark 2 and Matt 19 are Jesus being sarcastic need proof and not simply your say so.
The proof is in the pudding. We know that the Pharisees saw themselves as righteous (especially Luke 18.9, but also Mt. 23.28; 5.20; 6.1-4). Jesus often, through the Gospels, castigated the Pharisees for their false self-righteousness and the hypocrisy of it all (Mt. 23.28).
Second, they are clearly distinguishing themselves from the tax collectors and "sinners". The Pharisees were particularly scrupulous about their special rules on eating, and their abhorrence at eating with less scrupulous people, for which they are faulting Jesus. "Pharisee" is derived from the Aramaic *perushim*, meaning "distinct and separate ones."
Jesus's first aphorism is "It is not the healthy who need a doctor, but the sick" (Mt. 9.13), explaining that Jesus was right to hang out with those in spiritual need. He follows that with a quote from Hosea 6.6 that mercy should take priority over ritual religion, a criticism of the Pharisees who have elevated ritual purity over meeting the spiritual needs of people. Any true follower of God is a person of mercy, not self-righteous separation. He ends with "For I have not come to call the righteous, but sinners." You're right that his tongue is firmly in his cheek. Because these pompous religious hypocrites see themselves as righteous, they will hardly listen to the words of truth from Jesus. He will instead take his message to those who will listen to it.
> Jews don’t believe in original sin
The concept of sin is pervasive in the OT. They didn't necessarily believe in original sin, but they did recognize a universal sinful inclination, and I'm not sure the distinction is severe enough for your point to be valid. They consequently didn't believe in human innocence, which was your thesis. The OT view of sin is that it is a transgression of the Law, a breach of the covenant, and a violation of the righteous nature of God. Paul, in Romans 3, said that all Jews and Gentiles alike were sinners (Rom. 3.9) The ancients believed that all people were sinners, and that the Law was not a shield for them (Ps. 14.1, 3; Rom. 3.19).
Therefore, I don't just "take that position because you are forced to because of your desire to not have Jesus conflict with Paul." I take the position I do based on the teaching of all of the Bible and the extended positions of Jesus and Paul. Neither the Old Testament, Jesus, nor Paul subscribe to human innocence.
> humans couldn’t be righteous and keep the laws of Moses.
The Jews did believe, as you are saying that humans could keep the law and be righteous. That doesn't mean they believed in human innocence or sinlessness, but they believed that a person could be a good and godly person.
> because as I showed Jesus didn’t view everyone as a sinner.
You didn't show this. You quoted Mark 2.17, which is tongue-in-cheek, and you quoted Matthew 19.17, in which Jesus says that God is the only "good" being. He says "If you want to enter life, keep the commandments," but that's a far cry from saying that Jesus doesn't view everyone as a sinner. What follows in the text is a clarion cry that more is required than keeping the commandments. The man had kept the commandments, but something still was lacking (19.21). None of this, clearly, is a statement or claim by Jesus that not everyone was a sinner.
> Paul said sin is transgression of the law
You're right, but it's only a partial answer. Paul said a whole lot more than that. According to Paul, sin is...
* ignorance (Rom. 1.13; 2 Cor. 6.9; Gal. 1.22; Eph. 4.1)
* inattention (Rom. 5.19; 2 Cor. 10.6)
* missing the mark (dozens of times)
* irreligion (many times)
* transgression, the one thing you said
* rebellion
* iniquity
* treachery
* evil
* guilt
* trouble
* lacking fellowship with God
* impurity
* unbelief
> so if Joseph and Zechariah kept the law blamelessly then they were not sinners.
Therefore this claim is incorrect. Sin is far more than transgression of the law. "Blamelessness" for Joseph and Zechariah means they are good people (Lk. 1.6). It doesn't mean they were morally perfect. After all, Noah was called righteous and blameless (Gn. 6.9) but also a sinner (9.20ff.). Job also was a blameless and upright man (Job 1.1), but needed to repent (Job 42.3-6). But we know Zechariah was a sinner because he didn't believe the message of the angel (Lk. 1.20), and unbelief is a sin.
So, not so "simple," as you claim.