> HTML4 was the "sloppy" answer to XHTML

I think you mean HTML5, which exhaustively specified how to do parsing in a fault-tolerant, normalizing way. HTML 4 (and 4.01) predated XHTML 1.0, and HTML 4.01 attempted to take things in a stricter direction, introducing a "Strict" DTD that did things like drop the <font> tag, in pursuit of separating structure and presentation.