I don’t think Asimov drank while writing. I consider him a great writer.
They’re just looking for an excuse.
Asimov was afflicted with an even worse condition, he was an arrogant ass.
But hey, if being an arrogant ass, or douchebag, or drunk, etc., meant I didn't read an author or listen to a musician then I wouldn't read or listen to much.
Sometimes I think the less we know about and author's and other artist's personal life the better off we are.
I remember reading the first volume of Asmiov's autobiography and being fascinated by the man but then I grew up and realized he was less than admirable, but still a good writer.