Help me decipher this esoteric joke.
 

I'm reading this book called The Killing Joke, by Anthony Horowitz. It's a pretty funny thriller where the killlers are an Englishman, an Irishman and a Scotsman, to say nothing of many other classic joke references. But this is not a book review and I need your help.

All by itself on the first page, the book opens with the line: "There's this guy, goes into a bar..."

My copy of the book is from the library and a previous reader filled in his own joke to complete the line which I don't get it. Here it is with his pencilled contribution in italics (sic).

"There's this guy, goes into a bar... <i>and asks for a gene dead Artistic drink Ha! Ha! Ha!
The Bartender says - ye already had too many Patriarchal drinks!</i>

wtf? I suspect that the joker is making fun of esoteric wankers and the joke is utter nonsense. But shouldn't there be some kernal of humour in it; even if it is pretty lame? Have you ever heard this before? What's the gag?

I fully appreciate that deconstructing a joke will ruin it, but I thought I could put it to you for some help. I'll sleep better.

PS: Q: What did the elephant say to the naked man?
A: It's alright I guess, but how do you use it to eat?

I got nothing... sorry, but I appreciated your PS