It was neither backwards nor goofy for a man in 18th century Europe to create a system only his 18th century European peers could use (the only peers whom he could even come into contact with in 18th century Europe).
What actually would be goofy and backwards would be for this man to consider all of the world's cultures with whom he had never come in contact with, and try to create a system that worked for them. That would be very goofy and backwards, it would make him a crackpot.
The mere mention of this conciliatory statement for those "[pesky] leftists" (of which the author is one), the author is asserting that "Linnaeus was backwards and goofy but yet he made a good system!". Why does this even need to be said?
Do we call Confucius backwards and goofy for only writing his virtues in Chinese and only considering his Chinese peers? Why didn't he, or the Chinese (they had an empire and the means to do this), send envoys to the west so they could divine and predict what cultures would exist in a thousand years, allowing him to write his virtues in all of the languages and to consider all of the different mores of the world when writing his virtues? It's too Chinese! Or what about the Mayans, why didn't they in their backwards and goofy manner realize that a thousand years later their script would be indecipherable (for a while) to the European-language-speaking researchers of the future? If they had written in Latin we would be able to understand what they were trying to say! Very goofy and backwards of them. \s
The author's statement is what is backwards and goofy, and it's a cultural shibboleth that worked -- I stopped reading the moment I saw that, because to me it is a goofy and backwards thing to say.