Why do white Americans say these things?

A black woman in Denver was asked to sing the National Anthem (star spangled banner). She instead sang Lift Every Voice and Sing (Black National Anthem). Fox News had Marc Lamont HIll Ph.D (a black man) to speak against Charlie Brown (a white man) in which Marc says that people are blowing the whole situation out of proportion to those who were offended. If she instead sang God Bless America your Grand Ole Flag people would not respond the way they did labeling it as a disgrace as they did the Black National Anthem. I happen to agree that it was blown out or proportion. Of course race was brought into it in which many white folks (supported by comments in this youtube video) says that they're offended as Americans period, because "the original anthem stands for freedom from tyranny during a time when we were at war for our independence". Saying things like "we're living through the shoes of our ancestors" and we're not. We're living through a system of white supremacy believe or not and as a collective... white people reap the benefits. Saying things like "get over it" which is an insult to me because it dismisses my history and excuses white people from what they did. I'm sorry but I'm not going to get over my history for it shapes my future. Saying things like "pack your bags and leave if you don't like this country" after we invested blood sweat tears and time in a country that we helped build if not build on our own while slave owners looked on and remember we were forced here against our will and now you expect us to leave. If you want us to leave then give us back our resources that was stolen which includes gold diamonds land etc. Why do you think that white Americans say these things without stepping into the shoes of black Americans or maybe venturing outside their comfort zone to see why we see and do the things we say and do.