The quote can effectively be explored if it is contextualised properly. However, the concept of humanism in Africa relates to the desire amongst most Africans to practice what is called in South Africa, "ubuntu" - a form of Socialism and social awareness. What this means is that all Africans, irrespective of race, creed or colour, should share with others whatever bounty they have gained. This act of generosity should be free and not enforced. It should be an act borne out of grace and appreciation for having received such a gift.
Such grace was practiced in South Africa soon after it became a truly democratic country in 1994 when President Nelson Mandela extended an invitation to all South Africans to exercise humility and forgive the atrocities of the past. The "Truth and Reconciliation Hearings," led by Bishop Desmond Tutu was an actualisation of this request.
It is, however, very difficult for many, especially Black Africans, to heed to this call, since they have been deeply traumatised by the abuses of the past by especially foreign, colonialist regimes. Many leaders, unfortunately, opted to adopt the philosophies of their erstwhile oppressors and practice/d similar approaches in their governance. This perhaps explains the concept that "you cannot have African Humanism."