That is a pack of lies.
“First, he was not a ‘big figure in the KKK’.”
On the contrary, former CSA Brigadier General George Washington Gordon recruited former CSA Lieutenant General Nathan Bedford Forrest into the Ku Klux Klan precisely because he had the influence necessary to command a unit of the Ku Klux Klan. Forrest subsequently also had sufficient authority within the Ku Klux Klan to later dissolve his Klan unit when he determined the Klan’s attacks upon the black community was inconsistent with his aims.
“Yes, he was a member. The KKK was formed to fight Carpetbaggers, not Blacks.”
That is also a false statement, because many other people joined the Ku Klux Klan specifically to target Blacks regardless of any additional purposes others such as Nathan Bedford Forrest had in mind.
“And before we go there, the UNION ARMY exonerated him of responsibility for the Fort Pillow massacre based on eye witness testimony from UNION soldiers.”
There is another outrageous set of lies. before the Battle of Fort Pillow, Nathan Bedford Forrest was leading an attack against the U.S. Army and civilians in Paducah, Kentucky when he demanded the unconditional surrender of the U.S. Army command with the threat, “if I have to storm your works, you may expect no quarter....” Forrest’s use of the term “expect no quarter” means he threatened to refuse the surrender of the individual soldiers and would order their massacre instead. At the Battle of Fort Pillow Forrest again threatened the massacre of the defenders, “Forrest sent a note demanding surrender: “I demand the unconditional surrender of the entire garrison,...Should my demand be refused, I cannot be responsible for the fate of your command.” Later, one of Forrest’s own men witnessed Forrest’s role in ordering the massacre:
Achilles Clark, a soldier with the 20th Tennessee cavalry, wrote to his sister immediately after the battle: “The slaughter was awful. Words cannot describe the scene. The poor, deluded, negroes would run up to our men, fall upon their knees, and with uplifted hands scream for mercy but they were ordered to their feet and then shot down. I, with several others, tried to stop the butchery, and at one time had partially succeeded, but General Forrest ordered them shot down like dogs and the carnage continued. Finally our men became sick of blood and the firing ceased.”[35] (Wikipedia)
Later at the Battle of the Crater, Confederate commanders and their command repeated the massacres of Black Union soldiers and their White officers.
Since Major Williams Bradford, the commander of the fort, panicked and disorganized the defenders by shouting "save yourselves," many fled to the beach, while no one struck the colors and surrendered the fort. Therefore while the "massacre" was in progress, the fort and its defenders were not in a condition of surrender. This is after Bradford had twice declared he would NOT surrender the fort. A CONFEDERATE soldier had to take down the colors, and when he did so Forrest ordered all firing to stop and help restore order.
Since no formal surrender was declared, many Union soldiers surrendered themselves, yet many who surrendered had taken up arms again, causing great confusion in the battle.
Forrest himself had to personally intervene to stop the firing on the beach, thereby saving many defenders. If his intentions were to massacre the whole defending force for hostile or racist reasons, he would not have done so.
At the congressional investigation, a black soldier named Ellis Falls said that black and white soldiers were being killed in equal number, until Forrest gave the order to cease fire.
I'm not saying that Confederates were not enraged by the thought of black soldiers taunting them from the fort and then got revenge. There is just no proof that orders to do so were from Forrest himself.