[hackthemack]

That type of webpage style was quite common in the late 90s. Compare it to

https://www.circlemud.org/

I think the html editors of the time defaulted to some of style we now find quaint/quirky.

[thesuitonym]

It was just the style at the time. There weren't a lot of HTML editors, even in 2001, and those that existed typically defaulted to an entirely blank page. People mostly wrote web pages in something like an emacs, vim, or notepad. Dreamweaver and Frontpage existed back then, but DW was only really popular with professionals, and nobody ever really used FP.

This style was a popular choice because it was easy to write, and could be displayed by just about any web browser. Compatibility and low resource usage was important back then.

[phpnode]

Dreamweaver was extremely popular with amateurs too - they just didn't pay for it

[irdc]

Anything more complicated than this was just too difficult with the early HTML standards (there was no CSS).