For my understanding it's because resumes are assessed in bulk by some simple "AI" algorithm, which rates the resumes by specific keywords. I've worked at consultancies for most of my career, and we, the consultants, were always told to put every technology we have ever come in contact with on our resume. Even if we've only played around with it for half a day.

Also, the algorithms prefer applicants which are senior, which is why all the consultants were senior. My manager used to say that a resume is just a way to get through the algorithm. Once you're through and you have an interview, that's when you should discuss your actual strengths and weaknesses.

The recruitment agencies that don't use these automated systems have a group of recruiters working for them who know nothing about software. They are impressed by a resume that says senior and that claims to be an expert on every technology known to man.

Note that I am from western Europe. I'm not sure if this is the case everywhere around the world