Drug testing for Wale-fare

Can someone explain to me why I have to pass drug test so I can work and pay for Government run programs like Wale-fare but the sorry asses who use this program doesn't have to pass drug test to receive my money? I say institute drug testing for all on Wale-fare and cut out items like Redbull and Mt.Dew. For too long us hard working tax payers have been taken advantage of and I for one am sick and damn tired of it!