(Matthew 8:21-22) . . .Then another of the disciples said to him: "Lord, permit me first to leave and bury my father." Jesus said to him: "Keep following me, and let the dead bury their dead."
Actually, Jesus was not telling his disciple to treat other living human beings as though they were dead. That's not what was meant by the above scripture. While scholars vary on their interpretation of the above verse, you have to know a bit about the burial customs back then. When a family member died, their body was laid in a cave for a year while the flesh fell off. Then the bones were collected and placed in an ossuary. There was quite the controversy a couple of years ago about an ossuary that was inscribed "James, son of Joseph, brother of Jesus", but this was a Jewish custom which lasted from about 30 BCE to about 70 CE.
Therefore, the conversation Jesus had with the disciple could be understood to mean the following: The disciple says "Look, I'd like to follow you, but it's going to be a while before I can travel with you---at least a year because my father just died and I have to put him in the tomb for a year and then we can "bury" his bones." In response Jesus basically said "....Look, I'm not going to be around in another year, your father's already died and there's nothing you can do for him right now----you'd be better off following me rather than worry about burying the dead all over again in a years time."
So anyone who tells you that Jesus is telling his disciples that they should treat others as though they were dead, doesn't know what they're talking about.