The major argument that surrounded the Atlantic slave trade had to do with whether it should be banned.
Those who argued for the abolition of the slave trade were not necessarily against slavery, though many were. Others, however, simply argued that taking so many Africans as slaves was destroying West Africa and making it impossible for West African society to progress. They argued, for example, that the slave trade caused constant wars in the region.
Those who supported the slave trade did so for a few different reasons. Some argued that it was necessary in order to keep the British economy going. Others argued that slavery was not really a bad thing because conditions in Africa were so bad that even slavery was a better option.
Eventually, the forces opposing the trade won out and the Atlantic slave trade was banned by Great Britian in 1807 and by the US in 1808.