You don't get more wrong. ALL current DV and HDV cameras use firewire to transfer video to a Mac. That is fact.
Hmmmm I see a lot of USB 2.0 references on this list of High Def camcorders...http://www.bestbuy.com/site/olspage.jsp?id=abcat0403004&type=category
I think the real complaint is from the MiniDV owners and NO it's not a fact that all DV and HDV cameras use firewire. Most actually use USB 2.0. MiniDV cameras (which IMO are being phased out of the normal average consumer market and replaced with hard drive cameras) use Firewire and those are cameras referenced here.
But that list from Best Buy shows HDV cameras most of which have 2.0 interfaces.