The point is as a group, White people pay and over-represented part of the tax of funding SNAP, and as a group, receive far less in terms of benefits. The point is non-whites are consuming well beyond their "fair share" of SNAP. So when non-whites complain about "white priviledge" and the sort, they're already receiving more than they should be in terms of welfare, divided by race.
You are conflating 2 different numbers. The number I gave is the percentage of ALL WHITE PEOPLE in America using SNAP. The number you gave is the percentage of people within the SNAP program, who are white. Also, the 8.6% figure I'm now finding out is slightly high. It may be as little as 7.9%.