ATTN NEW USERS: I strongly suggest using a real, alter-ego email address from a reputable provider and using a Password Manager to securely keep tack of it. If you forget your email and password I cannot restore your account. These are good practices in general so stop being lazy.
Because monkeys in the 17th century had a very stressful life, going from job to job just to earn some bananas. Being a cat barber would surely lead anyone into heavy drinking.
According to this blog, the most widely-held interpretation is that drunken monkeys were simply seen as a fun thing to paint. However, the author argues that there was likely a deeper significance to these paintings; they were, he claims, a kind of early-modern Reefer Madness, meant as social commentary about the dangers of the new drugs that had become available to Europeans, including tobacco, opium, and distilled spirits.
It also has quite a few examples of monkey paintings:
I don't know. The author may simply be reading a modern bias into these paintings.