Remember in Fight Club when Tyler Durden says to the narrator, "I want you to hit me as hard as you can"? Close your eyes and imagine that, but instead of hit, imagine the word "degrade" in there. Now open your eyes because I'm going to flesh out that request.
A desperate person in a desperate situation will do a lot of things. It's really only by the thinnest margin that society works at all, but under the right circumstances any of us could go buck wild and kill someone to save ourselves, rob a store to feed our families, or drop everything and flee to escape persecution. But what the Sam Hell makes you want to pork someone for a McChicken?
Of all the shameful things one could trade for sex, McDonald's probably symbolically stands head and shoulders above all else, proud and tall like the despicable, never-hump-to-get-this-stuff thing that it is. It's not that it's somehow worse in practice than sex for an equal amount of money, which I guess is like $6 or so, it's that culturally, and spiritually, McDonald's represents everything you don't want penetrating you. Tell me I'm wrong, penetration enthusiasts. McDonalds is the go-to joke restaurant when you're talking about something cheap or bad for you. Any other would do, but because of its global presence and its place in our understanding of the world at large, McDonald's is the titan of sadness. And that sadness just grows like an illicit boner at the drive-thru when you hear about someone humping for a McDinner.
Donald Jones was the John, or the Ronald or whatever you call him in this case, who was caught by officers after picking up a lady of the evening and going through the drive-thru with her. After buying a meal for his rent-a-friend, he asked how she'd pay him back for it and the whole messy transaction came to a head, as it were. When police confronted the two at a nearby park, the woman was pulling up her pants, so this was a full-on consummation deal. You'd figure McNuggets, in a moment of starvation, might be worth a handy at best, but, oh, no. This was the real deal.