That’s probably the worst thing you could have replied with John.
What everyone is expecting is equality for all nationalities and genders. Equality for every person. To not be assumed anything before being spoken to. We are fighting negative stereotypes that have real world, large scale impacts.
You are just another white man protecting himself from being accused of being wrong. Unfortunately for you, you sit with the group that over and over again have been unable to see from others’ perspectives. Others will assume you won’t understand, that is your stereotype. Instead of playing into that by being defensive and trying to prove you’re right, try being empathetic and attempt to offer examples of how you will help. For it is “white men” who need to show empathy, grief and apologize even if it is not you specifically who is causing the problem. Maybe if you reflect enough you might remember examples of where you didn’t speak up but could have or said something racist that regardless of your audience, wasn’t good. Use those moments to fuel more positive efforts in these discussions.