If you don't find it funny initially, then it is very unlikely that you will find it funny after it's been explained. Nevertheless, I find it humorous because

If you don't find it funny initially, then it is very unlikely that you will find it funny after it's been explained. Nevertheless, I find it humorous because it is very unexpected, quite extreme, and seems to prove itself in a way (one of the ideas that it presents is that his coworkers don't give a shit about what he is doing. That he was able to get away with putting this into his acknowledgements seems to suggest there is some truth in that (of course, realistically, he wasn't going to be fired for it)). Kind of a combination of surrealist humor and shock humor. Today this sort of humor may seem a bit tired, but keep in mind that this was published a few years before Fight Club. "Jack 'n Zac" always kills me too. Such a great name for such an improbable drink.