Well, they did at my school. It was an important issue, since for much of the 19th century, a large part of Britain's defence expenditure (one-sixth of the naval budget in 1840) was devoted to the Africa Squadron, whose role was to suppress the slave trade, run largely by Americans.
This led the Royal Navy into action against ships from France, Spain, Portugal, Belgium and, particularly, the United States. There were also military actions on land against several African and South American countries, often in pursuit of American slave traders.
When the European powers finally agreed to accept the 'reciprocal right of search', the US and Brazil refused to comply. Brazil turned against the trade after Lord Palmerston ordered the seizure of her ships in 1850, but Britain continued to make war against US slave traders until Lincoln, in 1863, proclaimed the freeing of all slaves in the US (90 years after slavery had been ruled to be unlawful in Britain, by the judgment in the Somersett case in 1772).
Given that we spent half a century and a great deal of our money fighting the US slave trade, Ms Zeller's assertion that 'some Americans will say that, once again, Britain is exploiting black people for profit' shows a woeful historical ignorance and some ingratitude to her hosts.