iRobot Manager interview questions

Unfortunately this was a huge waste of time. I was really interested in the job and company, but interviewing with 14 people over several weeks wasted not only my time but theirs. Further, the interviews were of decreasing relevance. I met with the hiring manager, then the immediate team, then some relevant members of the broader team, then even broader, and so on. I'm happy to be meeting with all of those people, but people I'd barely work with shouldn't have veto power, so how/why did this drag on for so long?