In the U.S., I’ve noted a phenomenon I call Self-Selected Segregation. In the
physical world, there are enclaves defined by ethnicity, language, race,
heritage and other parameters. Throughout nearly the entire country,
anyone able to live in an enclave usually can afford to live somewhere
else. Not everywhere else, of course, but somewhere outside the enclave.
Yet, the enclaves survive because of self-selected segregation.
In the physical world, there are social and legal barriers to enclaves becoming exclusive and hostile to "the other." Regardless of race,age, sex, gender identification, sexual orientation, ethnicity, language or heritage, the law forbids owners and landlords from excluding "the other," to include the chilling effect of bias-based harassment. Social pressure dampens group actions hostile to "the other," but does not eliminate it. I've been the only native-English speaker in a a hundred square kilometers, the only one of my race in a hundred square kilometers, and elsewise "the other" on multiple occasions. Only once did I encounter hostility, but that was directed at my accompanying friend, who was a member of the area's racial majority.
The internet is an entirely different world. I participate in multiple online fora, each with its own focus. For those fora with a widely-inclusive focus, such as application of technology, discussion of music and arts, or discussion of literature, there is no "other." That is not true for those with self-selected segregation of a political orientation, or of the marginalized.. Many declare their purpose to be awareness and education, which is too often stymied by the members themselves..
These fora regularly devolve into echo chambers, with every member agreeing on everything with everybody else. "The other" is viewed with suspicion,and almost inevitably treated with hostility. When joining such fora, I have taken to stating "I am not one of you; I am here to learn." Members of most political fora immediately become hostile, many telling me to leave. Self-segregated fora of the marginalized typically tolerate me, until I trip over a term or mention something I believe relevant, but is an agreed apostasy among the members. The reaction is almost always extreme hostility.
Most recently, in a forum of a specific margenalized group, I searched my vocabulary and used a thesaurus to find the least-threatening/most neutral word to describe something, and chose "phenomenon." Another member replied that the word meant weird or strange, and was an insult. The member went on to find other words in the post to prove that I was biased against the marginalized, and another member piled on. The accusations became heinous. This did not disturb me. What disturbed me was that no one came to my defense.
I had been a prolific contributor to the forum, as well as one of its primary financial backers, for two years. I had stood up for every element of the group, and voiced regular condemnation of abuse directed at any part of the group. I was "the other," and abuse of me was tolerated, by people claiming to oppose abuse.
I submit that such groups are harmful to the cause of the marginalized. Abuse of the marginalized should be obliterated. It cannot be so long as a large number of people tolerate their abuse. When the marginalize silently tolerate abuse of "the other," they are approving of the precise behavior that allows them to be abused.