Unfortunately meta discussions are frowned upon too, so I shouldn't have made this comment either.
This isn't to say that humor should be verboten, or pun threads strictly banned - but they're definitely not what HN has been about historically, and arguably should not be encouraged if we want HN to continue serving whatever role it serves. There are more places like /r/jokes than HN on the net, after all.
That said, I agree with all your points... but we're humans... Even if most of our time is spent on science, we still get amused by the most silly of things; and if those things help support LetsEncrypt... Hurrah!
It isn't a question of humor, but of stock humor, which grows like crabgrass on the internet and quickly takes over. I think scott_s got it right years ago: https://news.ycombinator.com/item?id=7609289. Humor that clears the signal/noise threshold does fine here.
In a comment thread about somebody donating? You must be disappointed often.