Why do you get more time in jail for selling drugs then you would if you killed someone?

I dont understand that if a cop thinks you are selling drugs and you have some on you that you could get more time for that then you could for killing someone. i dont see the harm in selling of drugs. if people want to buy drugs to make themselves happy then they should be able to. The economy is so messed up these days there are so many people without jobs. so why should someone who is trying to make some money to support their family get more time in jail then someone who actually murdered someone and did some physical harm to another person.