It is so great to have you back. Your absence shows me how much I need your support and prompting of me to think about scripture and apply it. "Hamartolos" defining sinners in this context as the "unsavory" (10:56), or as you suggest "outcasts", is a context I can understand as to the meaning of Jesus calling the "sinners" rather than the "righteous". (14:55). This context I think is quite narrow, not a global proclamation, referring to those Jesus associated with in his formative ministry. The context is at that particular time, he had decided to recline with the outcast tax collectors, whom he had very specifically called to "follow me". (01:20). Globally, by contrast, Jesus did call the righteous and unrighteous alike to follow him, and was crystal clear in the dire hellfire consequences of not heeding that call. The Pharisees therefore asked not just a good question, but the right question as to what criteria Jesus was using in deciding to recline that day to a sumptuous meal with tax collectors. We know this was a limited context because Jesus elaborated "I desire mercy and not sacrifice" (15:22), yet the Gospels are replete with Jesus demanding sacrifice. Indeed, sacrifice is a co-theme with repentance and mercy. "I desire mercy and not sacrifice" was a limited context specific challenge Jesus issued to the Pharisees in answer to their good context-specific question-- Jesus answered "go and learn what this means". The lesson, it seems to me is that when it came to associating with outcasts, i.e. the "sick"-- as you take pains to explain brother Chad (14:50)-- Jesus is not there to demand sacrifice from them. Jesus healed many afflicted people, even resurrected the dead, but he didn't demand "sacrifice" from them in that time of need. But Jesus loudly and definitively did demand sacrifice from everyone else and all of us in the broader context of daily living, for it is a practical requirement of salvation.
God began teaching me what mercy meant when I was a child . I was raped by my uncle many times when I was 7, God gave me a vision of Him about to judge my uncle, He looked at me and said, " there is no mercy without forgiveness, He had me understand that without forgiveness, we remained prisoners, and I didn't want that. His Holy Spirit prayed in me a most profound prayer of such complete forgiveness for my uncle that it wouldn't be found on judgement day. Apart from the mercy He has shown to me, His prayer has remained in me for every single thing done against me and I love our Father so much for such treasure of His own Love placed in my heart always