This is totally alien to me. I could understand - though not relate - if you were offended, or just thought the use of the word "fuck" here was awkward or tonally inconsistent. But "puerile" and "why should I take you seriously" and "you talk like a teenager" is an absolutely ridiculous reaction to me. I've honestly not met a single person in all my life who reacted like that to a superfluous curse word.

Because you’ve decided that being performatively uptight is not advantageous to a life fully lived

I believe they are up for a noble cause. Please focus their self-quarantine manifesto rather than the "words" they used.

You know different adults from just about all the ones I’ve ever met, I guess.

Because it is not about who says it, but about the truth value of it - and the simple fact is that you probably do know some old people you would like to keep alive.