If a software generates such HTML code, then it is definitely crap. And I don't particularly care if it comes from Apple. This is an absolute low blow to everyone who deals with semantic markup and everyone who deals with accessibility. Similar to the PhotoCasting debacle, Apple once again shows that they unfortunately tend to be "outside nice, inside crap" every now and then.
And quite honestly - not only is the code a catastrophe, but also the generated URLs - has anyone at Apple ever heard of human-friendly URLs? Oh, what am I asking, they don't even know RSS Enclosures ...
More about iWeb's HTML can be read at Todd Dominey.