1- The Holy Qur'an tells us to "stay away" from alcohol. No where it says it is "haram". Whey then it is declared haram by the Muslims?
2- No where does the Qur'an command us to "stone" the adulters. The only command that is found in the Book is to flog them with a 100 lashes. Why then the adulterers and adultereresses are stoned to death?
1. The holy Qur'an does not always call something haram that it intends to prohibit. It uses other styles of expression. Sometimes a thing is already known as forbidden even through the innate guidance the humans enjoy. The Qur'an merely refers to that. For example you wouold not find the Qur'an talking on the evil of falsehood, treachery or the gooness of tuth, mercifulness etc. The prohibition of intoxicants (not the substance called alcohol) lies under the categories of things prohibited by the innate guidance implanted by God in human nature. That is why the Book does not explicitly mention it is haram. This means that the hurmat (prohibition) of drinking is clearer and more binding.
2. We believe that the punishment for adultery is a hundred lashes for all the offenders male or female. The stoning is punishment for another distinct crime termed muharaba and fasaad fi al-ard (creating disorder in the land). Sometimes a person does not only indulge in zina but becomes a dreadful rapist. His crime is not that of a simple adulterer. This man can be awarded the punishment of rajm known as stoning. For detail please refer to: Punishment of Rajam and the Qur'an