I doubt its HR people, it’s highly likely its employers.
If you don’t write the application for the job it’s going to be generic and b listed against the people who have written their applications for the job standing out far above yours. It shows you don’t have attention to detail and frankly don’t want the job. If an employer has 50 applicants (pretty low for tech) thats your competition.
TL;DR The harder you make it for an employer to justify hiring you the harder it is to get employment.