I guess I'm looking for a solid line of reasoning for why I feel strongly about drinking- and it's quite possible that I could be flat out wrong and there is no reason for me to feel strongly.

You can feel strongly about something without having to think there's a moral dimension to it.

I've also been talking to a friend about it and while my reasoning is generally along the lines of "Why?"- why is it necessary? why would you not want to be in full control of your mind? why do you need social lubricant?

You're assuming that somebody is more fully in control of himself when he is totally sober, but that's not necessarily the case. To use your 'social lubricant' example, suppose a person wants to be more sociable at a party, but he normally finds himself held back by nerves and anxiety, and he finds that he can calm the nerves and be more outgoing with the help of a little alcohol. Given that he couldn't bring himself to do what he consciously wanted to do (be more sociable) when he was sober, he arguably wasn't fully in control of himself at the time. Rather than losing a degree of control over himself, the alcohol might be removing an impediment to his own control over himself.

Now, you might think that this doesn't make any sense. Surely, you might think, the 'real person' is how the person behaves free of the influence of any external drugs, and deviations from that behavior due to drugs or alcohol or whatever are deviations from a person's true character. But we don't think this way about everything else. To use a dramatic example, somebody suffering from schizophrenia might be much less 'herself' when she's off medication than when she's on it.