What specifically am I being preachy about?

You called alcohol a "vice". Definition of vice from Merriam-Webster is "moral depravity or corruption; wickedness; a moral fault or failing." You are specifically asserting that people who drink alcohol are bad people. How is that not being preachy?

I do apologize then, as this was not my intention when I chose to use this word. Instead, I meant to convey that alcohol is a net negative healthwise, not unlike smoking cigarettes or consuming large amounts of bad food.

There are many shades of meaning to "vice"; it broadly indicates a weakness of character, not necessarily to the extent of making someone a bad person. If you know that alcohol is bad for you (and the people around you) and should not be drunk, and yet you drink it anyway simply because it feels good, is this not a failure of self control?

Although the slippery slope is a fallacy, down the road you speak is monkhood and the productivity optimization cult of recent times.

>You called alcohol a "vice". Definition of vice from Merriam-Webster

the phrase "every man has his vice" is supposed to be interpreted as every man is corrupt and wicked?