The browsers that don't support tables are generally older and for this reason they are discounted by these authors. The authors in this group are some of the most experienced on the net. They are very experienced and don't use many of the new style tools available to them. They rely almost entirely on content and the research required to compile the content. They are quite often academics who are used to passing the information from their research to other researchers or interested Netizens via the net.
Graphics are almost non-existent.
The style manual link from the last tutorial is a good example of this philosophy. To these authors a small logo of his department and school is about all the fluff you'll see from them. They may use a table but not necessarily for style but as a good way to display his raw data. Pros Supports all browsers. Good navigation because although long, the documents are well structured.