They don't. A table row has exactly the same recursive structure as a definition list, and will be treated the same way by a screenreader. It's kinda sad how many people like to play the "accessibility card" without any actual understanding of how those technologies work.
What screenreaders do have trouble with, however, is static layouts where the "meaningful" content is buried six levels deep, and often at the end of the logical document, just to make room for a bunch of navigation aids and advertisements.
That, however, isn't a reason not to use tables where they help. Also, note that with just a tiny amount of javascript it's possible to come up with a document that displays in a nice table layout and has a nice logical structure for screenreaders. It just requires that you get beyond the pedantry of the table.