i totally agree with you, that hastily taking drugs with no phsyical or mental preperation (knowing what it makes you feel, what it does to your body, how to help prevent negative side effects, etc) is completely WRONG.
i think the reason most people do that is simply because at one point they found out that government drug propaganda is untrue (read: exaggerated) and the drugs that are demonized (weed, shrooms, x) aren't NEARLY as bad as they're made out to be. so the person assumes that this goes for ALL drugs, that ALL drugs MUST be pretty safe cause you've always been told they weren't. said person may hear about a legal trip like dxm, find out that all that's needed is a bottle of cough syrup. they'll probably just assume that any old bottle of cough syrup is good, because they assume that if it's OTC, it must be safe. they end up getting robitussin sinus or something and OD on some fucking antihistamine. heh... they're not very bright, but they need to be shown that light, that drugs are TOOLS, not toys. once a person realises that, he or she will be changed forever (in a positive way... usually!)