The SPLC will not designate a "hate group" if there is any possibility that doing so will anger, rather than agitate its largely Progressive donor base. Money is everything.

In 1998, the Boy Scouts banned gay scouts and scout leaders from its organization and restated its commitment to exclude all gays from its ranks in 2002:

"The BSA reaffirmed its view that an avowed homosexual cannot serve as a role model for the traditional moral values espoused in the Scout Oath and Law." 

Despite claiming that ALL gays lack the morals to be Scouts, the SPLC said nothing on the matter until 2011, and then only said "The BSA doesn't mean to encourage bigotry."

http://wp.me/pCLYZ-1c

Why the double standard? Because many of the SPLC's donors were scouts or the parents/grandparents of scouts and tying the almighty donor to a "hate group" is bad for business. 

It's the same thing with antifa. Too many SPLC donors support the thuggery.