Chinese generally has two writing systems: traditional and simplified. In the 1950s to 1980s mainland China developed simplified chinese in a bid to make the language easier to write. Note that these are just different ways of writing the same characters: think cursive versus block. They are not different languages -- the vocabulary and grammar can be identical.
Traditional Chinese is used in Taiwan, Hong Kong, Macau, Singapore, and to one degree or another in various Chinese immigrant communities around the world. Taiwan is obviously the 800 pound gorilla here.
Taiwan has come to develop its own style of written Chinese -- think US vs British English but more nationalistic. So the question is: when Google Translate converts to traditional characters should it also be translating into Taiwan's written patois [not to be confused with the Taiwanese dialect]? After all, Google Translate does not differentiate between Britain and the US in English (it sadly uses British). And there are other groups which use traditional without this patois (Hong Kong, say, though likely not for long), albeit in fewer numbers.
The author does have one really good point, and that is that Google Translate is mistakenly describing traditional as zh-TW, that is "traditional as used in Taiwan". As long as it insists on doing that, it should also be translating into Taiwan's written patois. But what it should be doing instead is describing traditional as zh-Hant.