You’re 100% free to decline including it on any personnel file or application (with the exception of acting/modeling). It’s also self-identifying.
Consider that as a multi-racial pluralistic society - our values will be different than a European country whose major ethnic groups are the indigenous people.
We have an unfortunately long legacy of systematic racism issues. Communities or color experience slower emergency response times, fewer school resources and teacher pay, redlining and gerrymandered districting, food deserts, fewer public transportation options, and often fewer per capita polling stations on Election Day.
Until race stops being an observable factor for community outcomes, we still have a lot of work to do.
Many organizations see and understand this. As part of their sense of corporate social responsibility, companies make a good faith effort to hire from a ethnically diverse pool of candidates. If all your candidates are white - a company needs to ask itself if that’s a reflection of their own hiring biases or if that’s a systemic issue within the talent pool? It’s good to know these things - because industry surveys are constant - which help local leaders, non-profit organizations, colleges and universities, and governments do their jobs.
Meeting diversity goals is good for a variety of reasons. Importantly in capitalism, it’s good to investors because customers tend to prefer supporting diverse companies. Perhaps more importantly than that, different backgrounds offer different modes of thinking when it comes to problem solving. Crowd sourcing from a bigger idea pool is good for productivity.