Why are some drugs illegal ? why are drugs illegal in general ?

i understand some drugs like coke meth heroin are bad for you but some drugs like weed acid dmt arent. and either way why should anyone tell me what i can put in MY body or not ? i understand that yes maybe there would be alot more drugys but im not saying that you should be in the street druging yourself but if im in my house i know what im doing whos the goverment to stop me ? you can still have rehab and stuff but still this is the land of the free right ? so let people who want to do drugs let do drugs