The FW de Klerk Foundation has labelled the notion that apartheid is a crime against humanity "soviet agitprop" - propaganda meant to agitate.
This is in response to what it called the EFF's "vitriolic attacks" on De Klerk.
Before President Cyril Ramaphosa could utter a word in his State of the Nation Adress (SONA) on Thursday evening, EFF leader Julius Malema rose on a point of order, asking that De Klerk be removed from the National Assembly chamber's public gallery. De Klerk was seated there with former presidents Thabo Mbeki and Kgalema Motlanthe.
"He is an unrepentant apologist of apartheid who is not willing to accept that apartheid was [a] crime against humanity," Malema said, in response to recent comments by De Klerk in interviews commemorating his speech which unbanned the liberation movements 30 years ago.
"My submission, Speaker, is that, please, for us to have peaceful proceedings, we should ask the commander of Vlakplaas, apartheid apologist, a man with blood on his hands, to leave this Parliament because he does not belong here."
Several points of order followed but Speaker of the National Assembly Thandi Modise didn't entertain them and De Klerk remained in the chamber.
According to a statement from the foundation "FW de Klerk, former President and Nobel Peace Laureate, and his wife, Elita, had to endure wave after wave of vitriolic attacks by Julius Malema and EFF members of Parliament, clad in their trademark red boiler suits".
"De Klerk - who will turn 84 next month - sat impassively in the public gallery as he watched the spectacle below," read the statement.
"De Klerk has repeatedly acknowledged the grave injustices committed under apartheid and has sincerely apologised on a number of occasions to those who suffered under previous governments.
"These were more than empty words: he dedicated his entire presidency to the abolition of apartheid and the negotiation of a new Constitution that would entrench the rights of all South Africans regardless of race. He oversaw the process that culminated in the repeal of all the remaining apartheid laws."
The statement then discussed the origins of how apartheid would come to be declared a crime against humanity.
'Political initiatives of the Soviet Union'
"First we have to look at the origins of the charge: In November 1966 the UN General Assembly declared apartheid to be a crime against humanity - and in 1973 it adopted the Convention on the Suppression and Punishment of the Crime of Apartheid.
"Both the Resolution and the Convention were political initiatives of the Soviet Union - which had itself committed atrocious crimes against humanity that involved the killing of millions of people.
"The idea that apartheid was 'a crime against humanity' was, and remains, an 'agitprop' project initiated by the Soviets and their ANC/SACP allies to stigmatise white South Africans by associating them with genuine crimes against humanity - which have generally included totalitarian repression and the slaughter of millions of people," read the statement.
According to the foundation, some 23 000 people died in South Africa's political violence between 1960 and 1994 - of who fewer than 5 000 were killed by the security forces.
"Most of the rest of the deaths occurred in the conflict between the IFP and the ANC."
"None of this is meant to whitewash the injustices that were undoubtedly committed under apartheid.
"However, we need a balanced understanding of the past - not one based on a simplistic black/white, good/evil framework - but on a framework that reflects the infinite shades of grey that actually characterise history."
The foundation further states that the Truth and Reconciliation Commission found no evidence implicating De Klerk in the violence, "despite the fact that the Truth and Reconciliation Commission (TRC) clearly had an agenda to incriminate De Klerk".
"As for Boipatong, the TRC's amnesty committee found in November 2000 that IFP supporters who perpetrated the Boipatong killings in June 1992 had acted alone."
The foundation said it was ironic that Malema launched the "vitriolic attack on De Klerk" as he "threatened to commit a real crime against humanity when he said on 7 November 2016 that 'We are not calling for the slaughtering of white people - at least not now'."
In 1998, De Klerk challenged the TRC's finding that he had been an "accessory to the commission of gross violations of human rights" in court. The TRC agreed to delete the finding, but its report was already at the printers, and the finding was blacked out in the printed reports.
It is parliamentary custom to invite former presidents, deputy presidents and presiding officers, and De Klerk has regularly attended these events during the EFF's time in Parliament.