Juries are all very different. Each one takes on a unique dynamic. It is really very interesting to experience. I've personally sat on 3 juries (once a high profile local case where we were sequestered for 2+ weeks) and also, in my career as a paralegal, I have spoken to jurors many, many times. It is one of my favorite things to do. lol Per all jury instructions, the very first thing they do is elect a foreperson. Sometimes they go in and everyone is kinda respectful and there will be one person who has stood out as a leader...another vocal juror will nominate that person. More often than not, that person is promptly elected foreperson.
Other times, you will have a juror who is just aching to be the foreperson, whether they are the best candidate or not. What often happens in that case, is the other jurors hoping to start things off on the right foot as a united group in good faith, will just say, "okay, if you want it, you can have it". I have yet to see this guy's interview so I am only guessing by what I have read (including the transcripts) but my bet is he was one of these types.