So in essence, islam is more about social conformity, than the actual severity of the sin?
A missed prayer, or paying of interest or adultery are all sins that can be done behind closed doors, and noone would perhaps 'see' you miss a namaz. But drinking is often a social issue, where people can see you gulp a drink. I guess its the social stigma that makes people dislike it more than anything else? Its sad that even Islam has been narrowed down to a show and tell level.
Where did you get these ideas? You are assuming too much here.
No one sees you when you drink alcohol alone in the house too.