Why don't companies articulate what the candidate is expected to do? Like... «You will be maintaining a 10-years old codebase of a high-value low-traffic website built on JavaEE and EMF with guice and Lombok all over the place. It's a no-frills job, but we pay well».
So a company is going to tread the line between a job description that is so vague it won't appeal to anyone ("we build stuff ... using computers") and one so specific that it won't be accurate after the candidate accepts the offer.
Why does Bossbert write the Job Description - because he thinks he knows something.
Why does Catbert edit the Job Description - because if they do not then they have a hard time justifying their value.
Why does not Dilbert write the job description - because a job description that reads 20 pages is a bit much.
I recommend a website called Glassdoor. I used them to avoid a job, I was unemployed, and this company was interested in me. Reading on glassdoor, everyone thought it was the best place to work. Everyone except the IT people. They thought it was just atrocious, and the turn over rate was over 100% in IT. No thanks - I would prefer to remain unemployed verses entering that mess.
Alternatively you can go on linked in, see who works there, hopefully you know someone who knows them, get an introduction, and find the real dirt.
Perhaps you chime in to say how you overcome some of our concerns in that post.
Instead, they copy and paste phrases from existing job descriptions (internal and external). The more specific the phrase, the more likely it's not relevant to the new job, so the less likely it gets copied.
So what does the job ad contain? The most abstract and meaningless phrases collected from a bunch of existing job descriptions.
Rinse and repeat, and you get to the situation we have today.
Feedback welcome.
However, it's courteous to work with the person who brought it to you, and I assume it's to your advantage, since they have an incentive to get you past the gatekeepers.