It seems to me this is more ‘accident’ than ‘intent’. Much like the history of Europe, European philosophical thought exhibits a progression of thought and structure lacking I think in most of non-European philosophy. This progression is more amenable to a formal educational curriculum than collections of qualifying philosophical thought that do not exhibit any defined progression.
If for instance, you consider Plato, to Socrates, to Aristotle, there is clear progression from wild gesticulating theories and questioning, to a more structured and poised philosophy.
That being said, whatever can be done to highlight other marginalized yet deserving philosophers for enjoyment of their work is deserving of compliment.