Numbers 5:1-4: Different Law, Intolerant God?

In Numbers 5:1-4, God tells Moses to put out of the camp those who have a skin disease, those who had a discharge, and those who have become impure due to contact with a corpse, so that they would not defile the camp, where God dwells.  (I draw here from the language of the New Revised Standard Version.)  I have two questions about this.

1.  Does this contradict other laws in the Torah?  Granted, a person with a skin disease was to go outside of the camp, according to Leviticus 13.  But my impression from Leviticus 15 is that those with discharges did not have to leave the camp, but they simply washed themselves and were unclean for a period of time.  Regarding contact with a corpse, the law concerning that comes later, in Numbers 19.  There, I don't see anything about the unclean person having to go outside of the camp, but he is washed and performs rituals at the sanctuary.  I can understand why someone with a skin disease would have to go outside of the camp: No one knows when he or she will heal, and so, until that person is healed, he or she is ritually contaminating.  But someone who had a discharge or who touched a dead body doesn't necessarily have this problem, for he or she simply has to wash and will become clean after a certain period of time.

2.  The idea behind this law is to separate impurity from God.  Many Christians have appealed to laws like this to argue that heaven or the new heavens and the new earth will have to be a place without sin, for God is perfect.  Or many Christians contend that we need to be clean before God via atonement in order to stand before God in a relationship, and this law is part of that stream of thought.  Even some Christian universalists would say that people will need to be purified and forgiven before they can enter God's presence in the eschaton.  But, if God is so pure that he is not able to be around sin, then how did Jesus hang around with tax-collectors and sinners?  St. Augustine said that a righteous man is especially perturbed by the sins of others.  But was Jesus continually offended when he was hanging around tax-collectors and sinners?  How could Jesus even socialize with them effectively, if they continually offended him?  I don't know what went on in the mind of Jesus, but I think that he probably recognized that they were on an unfulfilling path and desired for them to live a better kind of life.  But I doubt that he was disgusted with them every time that they manifested their human nature.