God of Numbers putting a man to death for collecting sticks on the wrong day of the week?

No, you're right. You should also include the verses before those. It speaks of the laws for the Children of Israel and the laws for the stranger. The Mosaic laws were for the Children of Israel and that is something that people don't understand. It also speaks concerning those laws that are done in ignorance and those ones that were done willfully. There is leniency in those that are done in ignorance and there is a price to pay for the disobedient. This man was gathering sticks on the Sabbath and knew the laws concerning working on the Sabbath yet he willfully disobeyed. If they had not stoned him then that would show the Children of Israel that they too can do as they please even on the Sabbath. Jesus said if you offend in one point of the law you are guilty of it all. Praise God we are not under the Law anymore.