This is an old anti-pattern: tests that sound like they're about competence, but they're actually about "culture fit."
Example: Speaking at conferences. This sounds like social proof you know something about the industry, and have communication skills to boot. In many cases it actually means you are good at networking, have leisure time available to attend conferences, and get invited back to speak at more conferences because you're likeable and contribute to the conference's social scene.
In my own case, I have spoken and even keynoted multiple conferences. But I don't think speaking at conferences means much when hiring, unless I'm hiring an evangelist or community manager. If I'm hiring a programmer, I want to know whether they can program, nit whether they can talk about programming.
Anyways, I support your thesis that some (or even many) single-metric gatekeeping strategies that don't measure the actual skill required by the job are bad, and I suggest that many of them test for culture, not competence.