The numbers are different but the reasons are the same. White Southerners did not condemn the Klan because the secretly supported the Klan or were too scared to speak out.
How do you know "White Southerners did not condemn the Klan"? Since many, many more whites were lynched than blacks, the whole issue is absurd.
To try to link moral equivalency between the Klan and today's worldwide Islamic movement is intellectually bankrupt.