The Mystery Of Sam

Why did Azazel kill Mary and all her friends? That is still a big mystery. It was to cover up something about Sam. What was it and did John find out what it was? It seemed like Mary's friends and family were being killed as John tried to find out stuff. How do we know Sam's gifts weren't God given? Ruby made a comment about it and then said about them not being from God.
Azazel never got to finish giving Sam the blood he wanted to because Mary came in and she was murdered.
Azazel was an angel as well as a demon, so Sam was given what. Angel or demon blood.
When Sam first started having visions, if they were from Azazel, then why was it to help people. Why would Azazel want Sam to stop the other children from killing? In "Home" Sam's vision had nothing to do with Azazel. Also, Sam could sense things and he had the ability to move things with his mind.
After Sam was killed by Jake and died. How come we never saw him with a reaper? There has to be a reason for that. If the angels can bring people back to life. How do we know the angels or God didn't bring Sam back to life, not Dean's deal. Another thought, I had, what if Sam consented to be Michael's vessel when he died and Michael healed him and brought him back to life. If Sam was so special and he was going to be Lucifer's vessel, then why did Azazel let him die? Did Azazel know that Dean would make the deal for Sam? Or more importantly, was Azazel and the bad angels working together all along? They wanted Dean in hell to help break the first seal because John wouldn't break, so Dean was next in line.
Sam was immune to that demon virus, because he's evil already or evil can't effect him. Sam could drink demon blood, but he never turned evil the whole time. Sam was still worried about helping and saving people.
Sam can hold demons and send them to hell. I doubt Lucifer wants his demons to go back to hell, so why would Sam have that ability, if he was going to be Lucifer's vessel. Also, the demons couldn't destroy Sam. Look how Lilith was surprised when she couldn't kill Sam with her demon ray gun, or Samhain couldn't use it either on him. Sam killed Alistair, who was a demon,so how could he do that? How did he kill Lilith?
If the demon blood isn't what gave Sam his powers, than what did give him those powers. Why does everyone think Sam is evil? Dean doesn't want Sam to be anything, but a human. Maybe Dean is wrong in thinking that Sam is a monster and he has something evil in him, maybe what Sam has in him is good.
If God saved Sam and Dean from Lucifer, then he has something planned for both of them. Castiel came and helped both Sam and Dean, not just Dean.

I don't know where Kripke and Co are going with anything concerning Sam, but I think it's crazy that people still think Sam is evil in some way or that he's going to help Lucifer. How do we know that Sam isn't really Michael's sword and Dean is Michael's vessel?

I find it funny that people somehow want Sam and Dean to be on opposite sides. Dean on the side of good and Sam on the side of evil. When who knows which side either of them will be on? Or heaven forbid, they are both on the side of God. Would that be so terrible?

I think people just want Dean to have some higher purpose and Sam to be nothing. I think that's how Kripke and Co are going to trick people, but I could be wrong.