The reason why this is contentious is because it relies on how you are defining 'a police intervention.' Very few people I see debating this issue dispute that blacks are killed at 2.5x the right whites are by the police. What they dispute is that this disparity exists because of police officer bias, and they point to differing crime and geographic factors that cause the disparity. In that case, blacks and whites might be shot at the same right within the context of a given police interaction, but what that specific context is and the frequency of that context between black and white populations differs.
The 2.5x number isn't really disputed, it is the reason for it & the policy that is proposed because of it that is contentious.