Heroin is a more addictive and lethal substance (which would be harmful to the user and others close to the user), and the amount used in shooting up can be dangerously close to what would lead to an overdose, if it isn't already. Drinking a glass of wine wouldn't even have a very noticeable effect. While alcohol abuse is a serious matter, I don't think any rational person would consider drinking "a fine glass of wine" to be anywhere close to that, nor would they consider drinking a single glass of wine to be akin to shooting up heroin. Can a single glass of wine eventually lead to alcohol abuse? Sure, I suppose it can, but which do you think is more likely to lead to abuse, a single glass of wine or shooting up heroin once?
Now, what makes you think heroin is no worse than drinking a glass of wine?
First, heroin kills far less people than alcohol, but we'll get past that. I will, however, point out that the general public perception of the dangers of most narcotics is dead wrong, including the use of heroin. This isn't an accident, as the government has continually propagated myths to justify their insane crusade.
But, you're already leaping to conclusions with that first sentence. Unless you can prove that heroin use inevitably leads to more danger to people around the user (which you can't) your conclusion that it deserves to be a banned substance while wine does not is already on thin ice. Young black teenagers commit violent crime at a higher rate than any other demographic group. Should we, therefore, lock up all black teenagers? Of course not, says any sane person who isn't wearing a white hood. The same applies to heroin users. Simply because they may be more likely to commit crimes (this is debatable, BTW, given the prevalence of drunk driving) does not mean that heroin should be banned, while wine is not. Certainly you are aware of the drunk who beats his wife and kids?
To answer your final question, it's a question of deontological ethics, although I could make a case using consequential ethics as well. Is the act, in and of itself, violating the rights of another human being? Note: Not likely, not more than likely, but does the act itself directly violate the rights of another or threaten (again, directly, not increase the chances of said threat, etc) individual? It does not. Today, hundreds of thousands of Americans shot up heroin, and didn't harm another individual. We can stretch this to all kinds of actions. The mere act of drinking a glass of wine does not mean the person will get intoxicated and drive. The mere act of owning a gun does not mean that person will shoot up a school, etc.