Obama came out against Prop. 8 in July when he said "I oppose the divisive and discriminatory efforts to amend the California Constitution, and similar efforts to amend the U.S. Constitution or those of other states," Yes robocalls did exist that lied about Obama's views. How is that the fault of African-American people? Shouldn't that actually be the fault of the people who paid for those calls, which were funded by the mostly white LDS church?

And it doesn't make me racist to blame people who have hurt me.

You are assigning blame to an entire racial group based on the actions of a small group of people. You're ignoring the existence of black LGBT people and allies. You're ignoring that the NAACP of CA came out against Prop. 8. If you are blaming black people for Prop. 8, casting that blame is a racist action.