(I'm not sure in Drupal parlance what a "section" is, but I assume that blocks will become sections?) have titles, but designers often choose to have them not display.
I've looked at it, which is why it caught my eye, @ergo you are right, "block" would be the parlance for sections, but in my minds eye, although it took me a long time to get used to their "Drupal speak" it's about the closest thing to sections in non-designer speak, perhaps why it is so difficult to see? (for some of us!)
they are attempting to make up for theme designer accessibility ignorance/shortcomings from within the Drupal core.
with that I'm strongly tempted to disagree, this to me is a core issue that has cropped up and has been fixed because of the attention to accessibility rather than SEO or design..
The more I think about it the more I can see that while yes with both WP & Drupal the end user may well "expect" thing to just hide things themselves at the click of a checkbox the bit behind can be as simple as display:none or it is better thought out perhaps?
with Drupal6 you can either hide your titles or change them to suit, the power behind the "hiding" is as important for SEO as it for navigation/access - at least I think so