I can easily believe this.
I remember when I was working in my last year of training, a young (early 20s) single black British woman was admitted to the antenatal ward for care, complaining of feeling just not right. Staff, doctors and midwives, openly refused to believe her. They thought, for whatever reason, she was making it all up so the council would house her locally (hospital was some way away from her home address and in a naice area).
This was said openly in the handover, instantly prejudicing staff against her.
As the lowly student I was assigned to care for her, and being from where she lived, actually took time to speak to her.
Turns out she was staying at her cousins in the naice area, to help with childcare when she started feeling poorly. She didn't want to be in hospital but wanted to look after her pregnancy, which is totally fair.
I took her obs which were fine and noticed swelling in one of her legs. I suspected DVT and raised it with the junior Dr's and senior midwives. They were so dismissive and for the rest of the shift kept sarcastically asking about my 'dvt lady'.
I had a few weeks on study block and when I came back ended up caring for her during labour. Turns out the DVT was confirmed. And her baby was small for dates due to placental failure.
I was fuming on her behalf. Unfortunately the staff attitudes towards her never changed, for the weeks she was admitted, they all believed she was there to try and 'play the system'.
Guess what. All of the Dr's and Senior Midwives making these prejudicial remarks were not white British. They themselves were from India, Nigeria, Ethiopia, Iran etc.
It really showed me that racism is so entrenched and also not as simple as white people being ignorant towards black people. It's far more complex than that, but that's what happens when you create a system where you import your staff. You also import their cultural attitudes too, and sometimes that is racism.