Well actually there is a world of difference between Methamphetamine and Amphetamine (Adderall). They are in the same family like MDMA but the addition of a methyl group makes Methamphetamine a neurotoxin. "Methamphetamine is a potent neurotoxin, shown to cause dopaminergic degeneration."[1] So they although they share same traits, their hazardous effects are no where close to each other.

This is why drugs are complicated and different. Blanketing all "drugs" as bad while drinking Coffee, Whisky and Aspirin is just hypocritcal and dangerous.

[1] http://en.wikipedia.org/wiki/Methamphetamine#Pharmacology