If you establish a vast trading empire, and tell the often surprised new inhabitants of it that the empire requires their spices/ silks/ slaves, can you really be surprised that the more enterprising and adventurous colonised people gravitate toward the point of origin? Is it some sort of mystery that there should be more people from Algeria and Congo in France, or why there are so many Indonesian people in the Netherlands?
I feel a similar perplexity about many people in the USA making loud complaints about cultural adulteration despite a good quarter of the land having previously been part of Mexico and this being reflected in most of the place names (to take but one example). Some commentators object with an absolute straight face to hearing so many people speaking Spanish in cities with names like Los Angeles.