One must be prepared for the consequences of displaying flags or symbols or speech while in society. Carrying a nazi flag is also perfectly within your rights, but low self-control, low IQ people could definitely do you harm. Sometimes it’s better to be the grey man. Being in the right won’t matter if you are injured or dead.
Discussion
Of course, he needs to be prepared, but on the other hand, I always expected libertarians to defend ANYONE (even Nazis) to have any flag on their house, regardless of their own personal values or opinions. And I am often kind of disappointed by how much this is not the reality, how much the freedom only counts for things "I like" and not so much for things others like and I do not. But this way of thinking brings us back to where we have always been. Freedom of speech either IS or IS NOT. Nothing in between. No exceptions. No opinions. No "yes, but...". No matter what the flag was, even if it was the flag of the FED, the communists, or the worst shitcoin you know. There is simply no room for personal values, when it comes to standing up for freedom of speech, everything should come through the filter, otherwise there is no freedom at all.