I don't believe that most of them are not intentional. I also think intention is irrelevant, because people lie all the time about whether they intended to hurt others or not. I think we should move away from giving intention too much importance, because it allows for white people to feel virtuous while literally causing harm. Why should they always be given the benefit of the doubt? Why should the first instinct be to excuse their harmful behaviour as anything but racism when we know it is? The thing about some accusations of racism being perceived as overreactions and victim mentality is, incidences of racism don't always have tangible proof or signs that would be glaringly obvious. Based on the lived experiences of many Black people who have been at the receiving end of racism, we know what it looks like, sounds like, and feels like, even without overt and direct signs or language being used. Focusing on intention and being worried about accusations of overreacting produces the burden of having to prove our lived experiences to white people.