Why is ‘drinking alone at home’ considered a stigma in the uk?

I am going to come at this from the perspective as someone who struggles with alcohol addiction (which I do). When I drink alone at home it is not social drinking. I started drinking when I was younger and I was in a band so it was always in a social setting and even though I would be drinking after the majority of shows and sometimes go too far, it never felt as bad as when I drink alone in my home. What has started to happen is that when I feel down, and I feel like shit one of the first things that comes to my mind is 'I need a drink to take the edge off'. The crazy thing is that it works in the very short term. When I drink my mood does appear to get better but all its doing is taking me away from my issues and delaying the pain I feel when I come back to reality. Then you end up feeling worse than before you started drinking the day before so your mind tries to trick you into thinking 'Man I feel like shit again and even worse but, I need a drink again' and the cycle continues. I am aware this is not a problem for all people that drink alone but the stigma is that there are a lot of people that use drinking as a form of medication. And when you drink alone without any social aspect, it can easily degenerate into 3 day benders. Now of course this is not a universal thing, in fact most people don't have this problem. So my line in the sand is that I can't drink alone ever, its too much of a poisoned chalice but I imagine for a lot of people that is also their line. If you can have a drink of wine with your meal and leave it at that, that's great. Some people can get absolutely smashed on their own for one day and be ok with that and not drink for another 3 weeks. There is definitely a bias when it comes to the stigma of drinking alone and drinking with other people and not all alcoholism is the same. You can be an alcoholic going out with mates and you can be an alcoholic on your own, both are bad but for me they play out differently. One of my former band members died from Alcoholism he was both a social drinker and someone who drank alone but that's only because he was always drinking 24/7. He never drew a line, there was no line for him. If you are able to be honest with yourself and draw that line then good but I've seen too many people (including myself) who can't. And lets be honest the way alcohol works is that it impairs your judgement which can be actually good sometimes but I've seen where it leads to bad, with friends and family and it can be such a destructive thing.