At least five white supremacist-oriented groups exist in Second Life, as of this writing, and are visible in Search when you enter "White Pride" and other variations of those terms. I contacted Linden Lab about this a couple weeks ago, but haven't received a response from the company, even though these groups are in clear violation of Second Life's official Community Standards:
The use of derogatory or demeaning language or images in reference to another Resident's race, ethnicity, gender, religion, or sexual orientation is never allowed in Second Life.
One group (above) openly displays the Celtic Cross, associated with neo-Nazis, the KKK, and other racist groups, while another (below) references the "sacred 14 words", which is also associated with racist hate groups:
"14 Words" is a reference to the most popular white supremacist slogan in the world: "We must secure the existence of our people and a future for white children." The slogan was coined by David Lane, a member of the white supremacist terrorist group known as The Order (Lane died in prison in 2007). The term reflects the primary white supremacist worldview in the late 20th and early 21st centuries: that unless immediate action is taken, the white race is doomed to extinction by an alleged "rising tide of color" purportedly controlled and manipulated by Jews.
Another group purports to run a "whiteembassy" in one SL sim, "the place for the whiterace". I looked into the existence of white supremacist groups in Second Life when one SLer in the Avatars Against Trump Flickr group mentioned encountering a member of one in her own left-leaning discussion group: "We'd put up with his Libertarian agenda of attacking Progressivism," she writes, "but when he started with stuff about white being oppressed by everyone else - I tossed him. Went to look a few hours later to see just what sort of person I'd tossed and if there might have been any mistakes - and I found this."
Membership isn't listed in these groups, so it's difficult to know how large they are. However, white supremacists have been known to set up shop and disproportionately influence other Internet platforms which allow anonymous users (as with Reddit and 4Chan). It's surprising that Linden Lab, which just made an official statement against Trump's Muslim ban, has not yet done anything to address these hate groups -- but perhaps they're crafting a policy to deal with them.