Almost everyone complains about recruiters hammering them with calls and emails. If I were to call several startups, before I could finish my sentence after saying the word "recruiter", they'd likely hang up or dismiss what I have to say quickly.
Why does their market keep growing and getting saturated every day if this is the case? Especially since it's not hard for a company to just post their openings on job sites quickly and easily these days.
Recruiters are meant to be the filtering layer between the candidates and the company and to assist in finding candidates that fit company's needs.
Good recruiters (mostly in-house) are specializing in the field (say technical) and are very resourceful in finding good candidates (building relationships with people who are employed, etc) and also know how to filter candidates based on resumes.
Bad recruiters build their databases with candidates they find on web sites, thus not ensuring exclusivity but claiming it, and push any candidate they have to any company that hires. They are not adding value and waste hiring manager's time.
Founders and hiring managers don't hate good recruiters, they hate the bad ones. This is true for many other professions too, not just recruiters.
Also, since recruiters working for agencies get paid a fairly high placement fee (20-30%), hiring managers often prefer to find candidates themselves and use the money for salary or sign-up bonus, and they only start working with recruiters when they can't fill the position for a while (say 2-3 months).
Lastly, cold calls are awful - they are disruptive and rude. The best strategy for a recruiter is to find a candidate first and email an introduction to a hiring manager with a resume attached. If you have nothing to offer, there is nothing for a hiring manager to talk to you about. Many managers will allocate the early or the late hour of the day to hiring activities and don't want to be interrupted in the middle of their busy day.
- Do not ask what positions are open without checking the company site. Sounds basic, but 75% of recruiters calling me (in my Dev Manager days) did exactly that. Disrespectful to hiring manager's time and the reason why they want to hang up as soon as they hear "recruiter".