I set my area code to his hometown of Eastover, SC (29044), a filter of within 50 miles and an age range of 20-25 (in case he was presenting himself as older than 21.) I didn't find Dylann, but during my infinite scroll I did notice some trends relating to masculine performative standards in South Carolina that can be extrapolated to America in general.
This outdoorsy, hunting culture probably has a lot to do with the rural nature of Columbia, SC and its surrounding towns. It's the same reason that my Match feed for Vermont shows a lot of guys smiling next to their mountain-bikes, hoisting up a large fish they caught, or blowing pot plumes out from their nostrils -- there's just not a lot to do in the woods. And at a point in history, hunting was necessary for survival in these non-urban environments. But now guns serve more as talismans than tools, representing a vague idea of "freedom" mixed with a heavy dose of power and a sense of control.
Gun ownership has been a central issues in American self-identity for a long time, becoming intertwined with the mainstream masculine persona. Dylann Roof received a .45mm gun as a gift on his 21st birthday as a rite of passage into manhood. He also internalized white supremacist ideologies and had a strong identification with his Southern roots; he felt powerful in the role of a racial terrorist, aligning himself with a powerful history of inhuman violence, murder, and oppression of non-white bodies. During the shooting, he said that he was doing this because black people "rape our women" and "take over our country" -- incredibly outdated rhetoric of racial hatred that comes out of the 19th-century Cult of White Womanhood and the false accusations of lynch-mobs.
This portrait of Southern masculinity is not so simplistic in real life, though. There were also a lot of black men on the Match feed, one with the username "ImTheBlackGuy" (humorously suggesting a sort of deviance/outsider status in being the token "black guy".) But the Confederate flag still flies in front of the capitol building in Charleston, and the mayor still says we just need to "celebrate" what's good about South Carolina rather than have a conversation about institutionalized racism, #BlackLivesMatter, and what really needs to be done in order to exist together in the 21st century.
One point that needs to be acknowledged -- discussed brilliantly by Arthur Chu in Salon -- is that Dylann Roof was not the exception to the rule, not an abberant cultural outsider whose "mental illness" needs to be understood in the treatment of this crime. This was a hate crime, an act of domestic terrorism, and a product of white supremacist ideology that is not as safely pocketed into a subculture as we might think.