One reason that some african americans were patriots was because a few of the high people during that time were racist. (This does not just go to african americans. White people were also patriots)
One reason that some african americans were loyalists was because some of the people that were in high power were actually african americans. These high powered african americans were not interfered with, due to there were many other people that bad guys wanted to turn into patriots. (DURING THIS TIME, very few african americans were in high power)
I hope that this helped! Please! Please! Please do not feel offended! I was only answering your question! And I caps locked "during this time" because this racist situation was only a big problem during the american revolution.