I'm pretty sure this is a result of non-technical people calling the shots on what roles they're hiring for.
ROLE: Sr. Full Stack Engineer Level 5
MUST HAVE:
10+ YEARS JAVASCRIPT EXPERIENCE
4+ YEARS JSON EXPERIENCE
7+ YEARS PERL ON RAILS EXPERIENCE
Linux
Sketch / Adobe Photoshop / InVision
PhD in Machine Learning
And not to soapbox here too much but but sadly I actually have come across a job ad demanding "4+ years JSON experience"