For me it's usually just about getting in more miles. Whether it actually helps me with recovery depends on what kind of race I did. If it's a middle distance race, I find that not cooling down seems to correlate with very tight muscles and even some awful cramps. A light jog seems to be a way of stretching the muscles out and releasing some of the tension that high speed efforts require. With races 10k and longer, it seems to make no difference at all in terms of recovery.
Everyone. An easy jog feels really nice after you just obliterated yourself. Have you ever actually done a hard workout?
Your mechanics a recovery pace have little to do with your mechanics at race pace.
Amen. Science is great, but training is still more art than science.
You don't need to go jogging to clear lactate. Blood lactate levels will plummet after the workout or race regardless. Now, it's true that levels will stay SLIGHTLY elevated for a day or so, and that easy running can get them lower, but it's not because the lactate hasn't cleared properly after the hard effort. It's because after a strenuous effort you continue to produce slightly more for a period of time.