I've Had It With The WIne When The Social Politics Are Ringing In My Ears

I've complained about my job on here before and I'm afraid that's all I've done is complain, well I've had it and I'm done with it. I experienced a bit of a social issue that led me to the end of it. Now I'm fully aware of the fact that other people might find this a bit over the top and a bit self righteous but something about the incident last week just pushed my buttons. Maybe the fact that I still don't understand everything about city life got to me. Or maybe the fact that it made me feel incompetent or maybe just the fact that I feel I did nothing wrong. Or maybe it's just simply the fact that I kind of like to stir things up, but here it is, it went down like this, whether you think I overreacted or not, this is what happened. As a disclaimer this certainly is not the only reason why I chose to leave this job, it is simply the straw that broke the camel's back.
I was innocently pouring wine when a man came up to me and asked for a sample, he looked a bit "weathered" but in the store I usually work in that is not the least bit uncommon. So I poured him a sample as he was well over twenty one and I saw nothing wrong with it. He walked away and I did not see him again. About twenty minutes later I start seeing armed police officers patrolling the store and suddenly a security guard comes up to me and I realize that something wasn't right about him. The security guard tells me that this man was a homeless man and I cannot give him samples. More accurately I am to ask him for ID and then deny him a sample. Wait, stop.
I was trained to give samples to anyone CLEARLY over twenty one that is not intoxicated. Now, I'm sure anyone reading this is thinking "what an idiot how did you not know he was homeless?" Honestly, I kind of figured it out immediately after the fact, but I could not come up with a reason to deny him a sample, it was free and he's legally over twenty one.
Now I'm so sure someone can argue this with me, "he probably is an alcoholic" "he doesn't need the alcohol" "drain on society" and so on and so forth. I'm still subscribing to the school of thought that people are equal and I can't replace the nagging feeling that I didn't do anything wrong. Maybe he was an alcoholic but who am I to tell him he can't drink? Who are any of us to tell other people when and how tto stop our addictions?
I'm not really sure why I'm bothered by this and this is certainly not the only reason why I'm not doing this job anymore but it really got to me. Who is the better person and who gets to tell others how to control their vices? All this trouble for an ounce of wine seems unneccesary. Maybe I'm young and I just don't understand and anyone that wants to explain it to me please do because if there is something I'm missing I really would like to know. I'm just sitting over here lost in thought and confused about how we treat people who we should really be helping instead of shunning and isolating. That's my thoughts for the day.