There's a material difference between Han character writing systems and pronunciation based writing systems -- a Han character carries roughly the same amount of "meaning" as a "word" in European languages, and the written form is standardized and persistent, so it doesn't evolve the same way as European/pronunciation-based languages do (in which spelling evolves over time).

The relatively unique way Han characters work may explain the difference in the focus between traditional etymology that you refer to, and the etymology in the website. I'm not sure "history of writing systems" is a good way to capture what the site is doing... Anyway it's more of a issue of translation (of a traditional area of study in East Asia that might not quite exactly exist in the West)

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I suppose one thing about "Chinese etymology" is that every native speaker of Chinese seems to feel entitled to dabble in it every once a while. In recent years Hong Kong has seen a resurgence of interest in written Cantonese, and there has been no shortage of self-proclaimed amateur etymologists who put forward the most ridiculous claims that even a high school student could debunk... I contribute to a cantonese dictionary and we have a general policy of disregarding and excluding any etymology claims unless there are strong reasons to add it.