Fuck around and find out.

I'm annoyed with how apt this sentence is.

Hey, so she is a sex educator, and she didn't get chlamydia from a consensual open relationship partner. This isn't "fuck around and find out", and the fact that you think that this is funny or deserved on her part is disgusting.

Its a very funny juxtaposition, the fact that it's not what it looks like is even funnier.

As someone in an open relationship...

I've had it, I was barely symptomatic, and once I realized I properly communicated with any partners I'd had contact with and took my meds, and it was fine after a round of antibiotics.

It sucks, but the stigma is worse than the infection itself. It's an unfortunate risk that comes with open relationships.

Test regularly, communicate well, and things will be ok.

Tbh it's an unfortunate risk that comes with relationships, period.
Doesn't matter how many relationships one has, be it simultaneously or not. Practicing safe sex, testing and communicating well is the only thing that separates someone with STDs, and someone without STDs. I'd go so far as to say people who have open relationships probably tend to practice safety more often than those who don't

I dunno, at first pass it seems really slut shamey, then at another it seems to take the stance that monogamy is the "right" way to do relationships. "Of course they caught and STD, they have multiple partners, duh."
It is boomer humor

100% agree. It's easy to catch something and spread it unknowingly when you're lying to everyone around you. Being open (even in communication alone) dispels the stigma, and maintains everyone's decision making autonomy.

"If only they had a conversation..."