Lynching was used to lynch white criminals as well; when few small towns and counties had money for law enforcement it was incumbent on local people to police themselves and shut down violent offenders. there is zero reason to assume all those lynched were innocent victims, in fact there is little reason to assume that. Most lynchings took place during depressions, like the one in the 1890's.
If it was all just about 'racism n stuff' then there would be far fewer whites lynched and a lot more Mexicans than white, but hardly any Mexicans were lynched compared to whites. Many lynchings were also 'mock lynchings' where nobody was actually killed.
Most black lynchings took place in the South because that is where most blacks lived. Duh. The Klan was stronger in California, the Midwest, and Long Island in the 1900's than in the South, and in case they had little to do with most lynchings.
