No captcha?

Hello,
I am learning programming and just discovered this website. But I am curious, how does it protect its users from spammers (people who post illegal or annoying things) without a reCaptcha? I thought clicking this blue box is required to prove that you are not a robot, can you please share any javascript that you use for this purpose?
Thank you and have a nice day,
Brian

I've posted for many years about how awful Richard "RMS" Stallman is - the pedophilia, the ableism, the misogyny.

Inevitably, each time I do, pedo examine my receipts & then say "all those incidents are from years ago! he's changed now!"

NOPE.