The problem is NOT that a phone loses a bit of reception when you hold it in your hand. Indeed many phones do that. 5 or 4 bars don't really matter.
BUT:
The problem with the iPhone 4 is that it drops calls and loses the internet connection when you hold it in your hand. And other phones don't have such a issue.
http://www.youtube.com/watch?v=F6oflC4qo8M
The video is not waiting long enough for the slow bar meter to catch up. the bar meters always have a time delay built in to them, but the phone's receptions responds more quickly. That is all you are seeing...4 or 5 'bars' can mean alot...if you are in a weak signal area, which it appear you are in the video. When you see the bar start below 5 and fall more..you are in a fringe area already. The bars are weight to the low fringe end of signal by default.
You negated your own point.