Fascism isn't exclusive to a party, or conservative and not liberal. Fascism can exist in the far right or far left.

The SPLC is a hate group. They labeled Tea Party members "terrorists", attack what the right stands for, and attack Christian principles and values. I suppose many years ago their opposition to white supremacists got them legitimacy with the FBI and the media, but not today as they hate on groups they simply don't agree with in many cases. They themselves are considered a hate group by other groups.