So your argument is that he was black-friendly due to him taking money to represent slaves as their attorney? You realize that the legal field is notorious for lawyers taking whatever stance and defending things they don't agree with if it earns them fame or money, right?
So Key freeing his own slaves meant he was against slavery and wanted to help them? In that case, after he freed his slaves, why did he keep all of the slaves his wife inherited? Why didn't he free them? Why did he say that blacks are "a distinct and inferior race of people, which all experience proves to be the greatest evil that afflicts a community"? Why did Key want all freed slaves shipped back to Africa and banished from the U.S.? Why did Key, as DC's district attorney (I thought it was his brother-in-law, but it was actually him), prosecute so many abolitionists?
And in the most compelling argument to represent Key's stance on blacks and slaves:
Key likewise sought to crack down on the free speech of abolitionists he believed were riling things up in the city. Key prosecuted a New York doctor living in Georgetown for possessing abolitionist pamphlets.
In the resulting case, U.S. v. Reuben Crandall, Key made national headlines by asking whether the property rights of slaveholders outweighed the free speech rights of those arguing for slavery’s abolishment. Key hoped to silence abolitionists, who, he charged, wished to “associate and amalgamate with the negro.”
Though Crandall’s offense was nothing more than possessing abolitionist literature, Key felt that abolitionists’ free speech rights were so dangerous that he sought, unsuccessfully, to have Crandall hanged.
But, oh yeah - he took money and gained fame for representing free slaves, so that somehow overrides his entire life's work.