When you visit someone's country you are not just a guest, you are the model for everyone else who comes from where you do and who looks like you do. The assumption is that how you behave is how others from where you came from will behave. In an age where social media exposes everyone all the time, bad behavior gets seen and shown to others and conclusions drawn based on that behavior.
But rather than admit that this is a thing which exists, others just want to press tired arguments about race and racism. Which even if true, who cares? It's their country. They're allowed to welcome or decline anyone they wish. How arrogant are we really to think that we can dictate who and what others allow in their homes?
Amazing.