I disagree with how the question is framed, around whether someone
can do these things:
People can do all sorts of bad things; they can mentally abuse their children, they can gamble away all their family's assets, cheat their co-workers and customers, they can hate and do many other things to ruin their lives, their family's, their neighbor's, their country's and the world's. People have the right to turn the U.S. into a broken state like Somalia. People have a long history of causing death, destruction, and pain to each other; I think that amounts to the same point in your comment, and I agree it's irrefutable.
But who cares what I can do? Once we mature past childhood, it's meaningless; it doesn't inform our decisions. The question is not what can we do - who wants to do 99.9% of those things? - but what could we be doing? What are our obligations to our families, our neighbors, our societies and the world? What do we care about? What do we do well, where are we causing harm, and how can we do better?
Saying we can be racist - well of course. But it distracts from the real questions: What harm is being done? There is very well-established, serious widespread harm being done to tens of millions of people because of racism; it's gone on for generations. What can we do to make it better?
In most of the world, people (or at least some leaders) have chosen poverty, ignorance, and violence over liberty, and justice. In the U.S., people chose to do better - they could have chosen otherwise; I hope they continue to do so.