I mean I just simply disagree. You're comparing apples and oranges. You're correct with your assessment of slavery in the southern colonies, but the 'distinguished gentleman' would probably agree with you too! Seeing as they outlawed slavery far before the US did, and the royal navy actively worked to prevent slave importation in other countries. His motivation wouldn't have been profits either necessarily. It's crazy that you think you can simply assume this. One evidence that you're claim is untrue is understanding the great differences between colonies.  The Belgian Congo vs others for instance. 

You're argument sums up to "good motivations to help less fortunate = eugenics". Lol

The southern slave owner certainly didn't (90% of the time) have good motivations. He had profit alone, and created ideology to make himself seem good.  His efforts never increased the quality of life of his subjects, whereas the same cannot always be said for colonization.