There is a quality even meaner than outright ugliness or disorder, and this meaner quality is the dishonest mask of pretended order, achieved by ignoring or suppressing the real order that is struggling to exist and to be served. —Jane Jacobs
What makes a certain city, neighborhood, town, or any other geographical region interesting is the assortment of different individuals going about their business. From a zoomed-out view it just looks like humans acting on their own volition without any central control; which at the end of day, regardless of how conditioned some people are, is absolutely true.
Diogenes called himself a "citizen of the world" and I am reminded of this each time I step into a cosmopolitan atmosphere. In this environment having allegiance to a particular place is irrelevant or at best secondary to pursuing the various interests and hobbies shared by people in the given area.
Culture is the true distinction between peoples and is not always based in a given area; it's possible to find similarities with people on the other side of the world, while not finding anything in common with the person down the road.
Take surf culture as an example: Surfing is a fairly niche sport but encompasses a greater lifestyle revolving around coastal living as well as having it's own set of manners and attitudes. Whether you live in Southern California, Hawaii, Bali, Rio de Janeiro, or any other global surf hotspot, the individuals who partake in the surfing culture share a common interest that might not be shared with someone in the same location.
On the other hand, some places have a recognized uniformity; either in social or environmental patterns you'll notice a bland overcast of sameness wherever you look. I'm not just talking about isolated pockets of uniformity arond the block or in a neighborhood, but an entire region where the vast majority are engaged in the same ways of living. I'm sure you can find this anywhere, particularly in small towns throughout the world; though during my limited travel opportunities, I have noticed that even megalopolis like Tokyo, given its size, is not nearly so cosmopolitan as say New York.
Everyone's Different
Homogeneity is a purely aesthetic concern and ultimately if you've had the opportunity to critically observe social environments, you'll see it's evidently a matter of degree. There's no two persons strolling along who are alike, regardless of whatever they might have in common. Whether you like it or not, things are always in a constant state-of-flux and only by embracing this truth can you be optimally fitted for living in this world.
The only way any sort of social order can claim homogeneity as its main ethical characteristic is by using force; and as we all know this has been historically manifested through the State. Being pro-homogeneity is essentially denying the existence of the individual and taking away his freedom of association which is at the root of all collectivist and tribalistic thinking. People often take for granted the reality of heterogeneity, as if we can separate individuals into neat boxes; often these are folks who yearn for life and interactions with people to be the way it's always been.
There are those who claim traditionalism or conservatism as the mode of thinking which brings about an orderly civilization and must be protected at all costs. Recently, this idea has caught some steam as a sort of reactionary approach to all the consequences of so-called liberal(not classical liberalism) agendas and cultural marxism the world has been under for quite some time. It's even caught on with prominent freedom advocates as they believe going the opposite way is the only "pragamtic" method available to ensure liberty.
Yes, there are a few traditions and customs that would perhaps be best if they are upheld, such as classical learning, property rights, and family; although as an all encompassing philosophy it's frankly naive and counter to anything based on reality of the world we live in. In fact, absolute traditionalism is a revolt against nature, it assumes that generations can and/or will uphold previous ideas about how things should be. I wonder if maybe supporters of such doctrine have an inferiority complex and feel resigned to the fact that they don't have the power to change society.
With some life experience anybody will be able to tell that heterogeneity and it's parallel cosmopolitanism, are inseparable to liberty.