My dad drank very heavily for many years. My mother never cared because, in her words, "There was always enough money and he was never a mean drunk."
I have seen studies that have concluded that a lot of behavior that gets blamed on drugs and alcohol is behavior they were looking for an excuse to engage in. They drank to facilitate the socially unacceptable behavior. So the cause and effect relationship is the opposite of what gets claimed.
In other words, they didn't do a terrible thing because they were drunk. They got drunk so they could do the terrible thing. (Example: pedophilia)
I have loads of sympathy for an addict's inability to stop using. I am convinced that most addiction is literally self medicating for often unidentified issues.
But I have damn little sympathy for an addict using their addiction as an excuse to crap on me. I don't buy it. I don't think having an addiction inherently leads to uncontrollable bad behavior that they just can't help (aside from rampant foot in mouth disease, which I also sometimes suffer due to my medical condition). I think that's a lie that they keep telling because it works.
I believe drugs should be decriminalized. I think the need to hide it fuels a lot of bad behavior that isn't due to the drug per se but is due, instead, to bs social factors. I believe you should be able to imbibe whatever you want. It is your body. I believe people need very supportive environments when coming off drugs because withdrawal is a bitch and people really do crazy stuff at that time. BTDT having never been an addict thanks to a serious medical condition.
But I do not believe in simply excusing repeated bad behavior because someone drinks or takes some other drug. We don't say people with medical conditions who are permanently on medication for it are excused from standards of behavior. So I see zero reason to say that about addiction.