PR are not the place for jokes. Developers have enough to do managing their projects, they don't need to waste time sorting through jokes.
You might say, "it's just one joke, what's the big deal?" One joke, attracts others. Everyone thinks they're funny and their joke with worth everyone else's time to read it. If PR become a place that's acceptable to make jokes, it'll be flooded with noise.
There's a well-established tradition of pull requests and issues being used for commentary and humor.
Here's a selection. The first one is by the founder CEO of a company with a ~$1B valuation that's prepping for an IPO and is very similar to the one everyone here is complaining about. The second one has comments from a couple well-known tech folks. And so on...
