An authority would be someone from the community that has actually done the historical research and has real insight and data backing up why reparations are justified and necessary. That person should also be generally be accepted by the community to hold a position that is in-line with the majority of the community. Again, I don't think any of that applies to this guy.
You'd have a point if Blacks were the only group they did shit like this with, but we're not. It's a common tactic used to shut down advocacy for any group. When gays rights were threatened, the got Milo to go around downplaying what was being done to gays. When Jews are being attacked, they call up Ben Shapiro to defend white supremacists. And once again, blacks are not the ones that invited him and blacks making a fuss wouldn't have prevented him from being used the way he was. So again, this is not proof any any way that blacks are too welcoming.
Now if we want to discuss whether blacks are too welcoming or not that's fine. I'd agree that blacks can be welcoming to our detriment at times. Still, it really comes down to what kinda people you want us to be. Should we be ourselves and take the risks, or should we lower ourselves and be more like whites. If a white family falls on times and is force to move into a poorer black area (this has happened quite a bit historically), should we as black people behave like white people and treat that family like shit just because they are different? Or should we be ourselves and embrace them if that's what they seek even knowing that depending on who they are they might betray us in the future. There is no easy answer to that really, but if I despise the way white people behave at times, I'd rather not take on those despicable traits. That's just my stance.