While the sentence seems to have disappeared from the article as of this writing, I have to admit that I have a bit of a problem with the fact that it was even there at all. Regardless of what you think about J.K. Rowling and her transphobia—and wow, that's probably going to be a whole other post on here eventually—I deeply disagree with the idea that being an adult has to mean that the only fun you're allowed to have involves raising children, exchanging pleasantries with co-workers, and occasionally going out to dinner (probably for a work thing). There's this idea out there that once you reach A Certain Age—and nobody really says what it is, but it's probably somewhere around thirty years old—you have to become dull and boring and just completely give up anything that isn't 100% serious and practical.
Quite frankly, fuck that shit.
As far as I'm concerned, even though we carry the responsibilities of adult life, adults are allowed to be silly. We're allowed to be creative. We're even allowed to make utter fools of ourselves in front of other people by making references to pop culture things that have since fallen out of style and/or favour. I'm actually quite in agreement with the sentiments expressed by Randall Munroe in this xkcd comic—that people who are grown-ups now get to decide what that means to us. Growing up doesn't have to mean that you never have fun or make people laugh. It just means that you have different responsibilities and more demands on your time.
Besides, life is hard right now. The cost of living is unconscionably high. There are two major conflicts happening with the potential for more, and in most of the world, financial policy seems to be focusing on making sure that all of the money gets funnelled to those who don't need it and away from those who don't have enough. Climate catastrophe abounds. So does human tragedy. We need positive change and we need it yesterday.
We also need to add what joy we can to the world. As long as we're not harming others, that is more than okay! Sometimes we need a bit of silliness, laughter, and mirth. Those who roll their eyes and make snide comments will do so no matter what; personally, if I'm going to encounter the petty unpleasantness of small minds, I'd rather do so in the company of someone who's trying to make the world a better, shinier place, even if it's only temporary.
In the words of one of my favourite Tumblrs...
"It is my solemn and sacred duty to make the vibe as silly as I can, and with your support we could achieve maximum silliness."