First, no one said the SPLC is the final say for this.
Second, do you have any examples of an organization that the SPLC deemed a white supremacist that wasn't?
Second, do you have any examples of an organization that the SPLC deemed a white supremacist that wasn't?
Here's a particularly egregious case where a UN affiliated group was labeled an extremist hate group and the SPLC wouldn't relent even after evidence was presented: https://www.newsweek.com/splc-nawaz-million-apologizes-98187...
It seems like they made a mistake in this case, clearly, but I don't know if you can extrapolate from that that they acted in bad faith.
At least read your own link, please. I get what you're saying about the settlement but they could've just paid out and not gone to such lengths explaining how they felt they'd gotten things wrong.