U.S. President Donald Trump delivers a closing speech at the World Economic Forum (WEF) in Davos, Switzerland, on Jan. 26, 2018.

GENEVA, Jan. 26 (Xinhua) -- The South African business leader who called for a boycott of Donald Trump's closing World Economic Forum speech on Friday afternoon has explained why Africans were angry with the U.S. president and why some of them did not attend his Davos speech.

Bonang Mohale, CEO of the lobby group Business Leadership South Africa, wrote an open letter to President Trump before the WEF meeting in which he condemned the discourse of the U.S. leader, the website of the national broadcaster Swissinfo reported on Friday.

"We have read with consternation reports of your derisive comments characterizing African nations and others as 'shithole countries', and questioning why the United States should allow immigrants from our continent, or other similarly described nations like El Salvador and Haiti," Mohale said in the letter to Trump.

He noted Trump's reported Jan. 12 comments which stated a preference for immigrants from "countries like Norway".

Mohale said many Africans were well aware of the serious challenges they faced such as poor governance, unacceptably high unemployment, inadequate public health care and education systems that, while improving, remained below the levels needed to lift them from poverty.

"Some of these challenges are self-made, (but) many are the inevitable result of centuries of colonization and its aftermath. Many of us are clear-eyed about our difficulties and how to tackle them, and are doing just that," said the South African.

Noting South Africa's legacy of the racist system of apartheid, Mohale said in the open letter to Trump, "Many of us will be boycotting your address to delegates at Davos in protest against your divisive comments and continued failure to unequivocally apologize."

South Africa's deputy president and newly-elected leader of the ruling African National Congress, Cyril Ramaphosa, left Davos before Trump's speech.

He said he had hoped President Trump's presence at the 2018 WEF meeting would help stimulate a debate that inspired commitment to a world premised on "basic principles of humanity, inclusiveness, respect, tolerance and forbearance".

Mohale said such a world is "an alternative, in other words, to a world where walls, disparagement, and hate dominate the discourse of the leader of the U.S."