So, Trump moved his Tulsa, OK rally from June 19, aka Juneteenth, to June 20.
If Trump had "many" African-American friends, why not hold the rally and celebrate Juneteenth, and provide an education oriented speech which many of Trump's white fans could use right now?
Trump knows he does not want to celebrate Juneteenth, or anything relating to African-Americans. He moved it to the 20th to stop the juxtaposition with Juneteenth. It should not be lost on anyone how Trump is no longer using "very fine people on both sides" remarks he used during and after Charlottesville protests, where many in the pro-Trump/pro-Confederate monument side were pretty scary in their racism and anti-Semitism. Now, faced with multi-colored protestors, mostly peaceable, demanding reform of the racism inherent in our criminal justice system, Trump's remarks are about crackdowns against protestors, continued criticism of the protestors, as well as unending exhortations in favor of police and National Guard forces--when there are so many recorded instances of police and National Guard overreach and abuse in responding to the protesters.
Trump moved the date of his rally, practically unnecessary in Oklahoma, a state he remains slated to win big in November, in order to make sure his pro-white nationalist message did not have to be tempered.