Not sure where polite disagreement can be thought hostile. Perhaps those who thought-up and enforced the idea that black people should occupy different seats on buses would not have been thought hostile by some?

In my book the attempt by one racial grouping to impose their thinking upon another - is about as hostile an act as you can get - short of actual physical combat. For it will probably lead to this evenually - if it is not addressed and changed.

Any attempt for one individual to claim to speak for any huge racial grouping is also of concern - whatever that grouping may be. For the thinking within that grouping will be very disparate.