Part of the problem is how successful government propaganda has been against pot. Pot was criminalized in the early part of the 20th century, partially on racist grounds (it was characterized as the 'black' drug). Unlike alcohol, which managed to overcome prohibition, pot had never been immensely popular among highly influential populations. By the time pot did gain in popularity, the government had already taken a strong negative view of the drug, a fact that wasn't helped by pot's role in the hippie/anti-war movement of the 1960s and 1970s. Since then, the government has promoted the view that pot is a terrible, harmful drug quite successfully so, although this is untrue (alcohol is arguably quite a bit worse in virtually every way) the general public tends to think it is true. Widely believed misinformation and a strongly entrenched war on drugs helps maintain pot's criminalized status. Such a shame.