Fwiw @enginewitty, in the HW discord, I cited a source for text on a different post of his. He corrected me and told me what website he'd actually gotten the information from, yet refused to include the link in his posts because (paraphrasing) he didn't have to.

And no one is saying (that I've seen) there has to be a link to a website, but the source of content (text, photo, or video) needs to be clearly cited to avoid accusations of plagiarism. That's how I've always understood it.