A personal opinion
I'm not in the industry although I am one of its customers from time to time. I'm also someone, regrettably, with personal experience of addiction to alcohol and almost 25 years of freedom from that addiction. I also know an awful lot of people similarly afflicted who have either recovered or still persisting in this behavioural disorder (or "illness" if you prefer.)
Of the thousands of stories I've heard from fellow alcoholics over the years, and the literature I've read on the subject, I can confidently say that all sectors of society and every profession is afflicted to some degree by this problem. There are plenty of anomalies - for example the medical profession is over-represented: I have no idea why. There are also firm genetic correlations; if you have someone in the immediately family with an alcohol/addiction problem your chances of also having one are a multiple of the statistical general population average.
For anyone interested in the numbers and the sociology Harvard Medical School have been running a long-term prospective study of this affliction, the results of which are published as "The Natural History of Alcoholism" in various revised editions.
I'm sure that the aviation industry has more significant safety problems than alcoholism. However I'm equally sure that it includes an equivalent proportion of alcoholics, more or less, to the general population. That'd be quite a few people, pilots included. What often escapes people's understanding where this phenomenon is concerned is that alcoholism is frequently managed by the functioning alcoholic so that at a superficial level their performance is not obviously affected. Quite often it's only when some crisis point is reached where their condition becomes apparent to their colleagues, family and friends - although those closest are obviously more likely to witness the underlying dysfunction. So there are probably plenty of alcoholics flying aircraft whose blood alcohol content is nil or legal.
Alcohol is so integrated into western society that the problems it causes are frequently rationalised away. But it's an addictive drug, just like heroin - although the physical dependency is slower in onset. And the functioning alcoholic who is never, ever drunk on the job (any job) is still an individual whose performance is compromised, subtly or otherwise. Choosing to look the other way doesn't do functioning alcoholics any favours, but that's what we often do.