It's inaccurate to say that nearly every culture is against "drugs" -- nicotine and caffeine are both relatively powerful drugs, and are widely accepted by most cultures on Earth, freely sold in vending machines and at corner shops.
Moreover, most cultures accept the use of (generally poorly understood) mind-altering psychiatric medications.
The question is why cultures accept some drugs but not others.
Moreover, most cultures accept the use of (generally poorly understood) mind-altering psychiatric medications.
The question is why cultures accept some drugs but not others.