Apart from the far right, no one ever openly admits to being a racist. Everyone will swear blind they are not racist.
Also people are generally not taught to be racist. It's ridiculous to claim that a child cannot be racist because they were not taught to be racist.
Most men have never been actively taught to be sexist. Most people aren't taught to be homophobic. Children pick things up through their interactions with those they spend time with, listen to, etc. Moreover unconscious bias is baked into our experiences.
The greatest fallacy is that racism is dead and only a minority of people are racist. Thankfully, after several studies and reports the government, academics, and workplaces, including schools are finally realising that racism is alive and well. It had never gone away. True it's a minority that will openly use racist language but the gast majority remain complicit in perpetuating everyday biases that's wrapped into our institutions and how we think about others.
No longer can we ignore this problem. No longer should we say "what about our feelings", "we are not racist", "they have a chip on their shoulder, they are playing the racecard, political correctness, blah, blah blah". No longer should we try to silent the voices of BAME people, refusing to hear about their experiences, discounting their feelings, and acting as if racism is imagined, that it is confined to the past.
The damage done to young BAME children from young must be immense. The impact on them as adults and how they view and respond to the world cannot be understood by those of us who never had to consider our race as a barrier.