If auto line break were to be implemented, the board would probably have to offer the input text box in two flavors: Basic (where you have the auto line break) and Advanced (where you do your own formatting).

It is the same reason some people use Frontpage, Dreamweaver, etc. to mark up a website; some use simply Notepad or something plain.

In reality, auto line break could be one of those seemingly trivial problems but not necessarily trivial to a computer. If you mean "line break" as literally "\n" wherever they appear, that's easy (but it will break many other HTML code, such as a table unless someone enters a HTML table all in one line).

If you mean "line break" as "paragraph" that actually could be very hard. It might look "obvious" to human eye what a paragraph is but it's very for a, say, HTML parser to distinguish because it can only read data, not content.

As to the second "hypocrisy" or inconsistency, that's a good catch. But since the site has been up and running for a long while, not sure those errors or warning messages matter.

Eventually, the content of the site that people see is more important than the code behind the site that people don't see.