A resume is a MARKETING TOOL that presents you in the best possible light for the purpose of getting invited to a job interview. The resume is written for the reader be it an H.R. professional or a hiring manager. If you know who is receiving your resume, write it accordingly.
When an HR professional reads your resume, they are generally reading it to screen you out. An advertised position may attract 200-400 applicants so HR is looking to eliminate all but 5-10 potential candidates. HR does not know the intimacies of the position like a hiring manager does, they rely on what they are told as to which resumes attract them and which ones do not.
A hiring manager knows more specifically what type of person they are looking for to fill the job and are hoping with every resume they read that YOURS is one to be short listed.