That's odd; at every tech company where I've interviewed, the majority of the interviewers were potential peers on the team (or from another team, to have an "outside voice"). The hiring manager is usually mainly there to judge culture fit and, if they like you, to help sell the company.

At the companies where I've worked and have interviewed people, the hiring manager would of course have veto power, but would never hire someone without the agreement of the team.

At my current company (Twilio), even the first phone screen (after a possible initial recruiter call) is done by a team lead or member of the team. But often the candidate doesn't end up on the same team as the phone screener, since we don't always know what team would be the best fit until after the screen.

I think of hiring as everyone's job, as it's right up at the top of the list of things that will determine the course of company culture over time.

(Shameless plug: having said all that, if you're an Android developer who enjoys building frameworks and APIs, email me at my HN username at twilio.com.)