Why should we not drink?
To be natural is obeying the Hukam of the Almighty. Whenever one goes unnatural, he defies the Hukam. Cutting the hair, provided by the Almighty, is unnatural. Eating meat, is unnatural, because the structure of teeth of man is to be only vegetarian as compared to animals, who have their teeth specially structured to tear apart the flesh. Drinking alcohol is also unnatural, as unlike water, it affects badly the senses, and attacks organs to lead them to failure and other deadly diseases. .....
Err no.
Humans are omnivores and have both types of teeth. We have Caninses as well.
Alcohol is contained in many medicines and can help medical conditions (in moderation).
As for Hair....it's not unnatural to cut, we choose to keep hair because we are Sikh.