This is an excellent observation and one that may have skewed the stats. Here in the UK we do have a resident BIPOC working class, descended from those who entered the UK in the 1940s after the Empire collapsed. However that's not the same state of play as the US, so your point is well made.

Where the UK may differ is perhaps the other way. We have a significant influx of white working class from other countries as a result of being in the EU. These people were predominantly from Poland (early 2000s) and then more recently from Romania and Buglaria. This may have skewed our working class white figures too - and there was certainly a lot of Xenophbia here that wasn't dependent on skin colour.