I don't think I want the government to be spending money to ascertain the quality of recreational drugs -- it seems like an endorsement of such drugs. In theory, brands that earn a reputation for high quality could develop.
Why not? Bad/deadly drugs, particularly due to cross contamination, are a public health crisis. Making sure a drug isn't going to have fentanyl in it is no more an endorsement than making sure a beer doesn't have bleach in it