I don't know about 'dangerous'. :)
I thought the mention in Walker was much more subtle than say anything else on the CW or what Chibnall is doing with Doctor Who at the moment. I stopped watching The Rookie, so I don't know how they handled things. There's acknowledging ethnic characters and blending their personal challenges into the overall stories and plots of a show, and then there's beating the viewer about the head with a particular message, sacrificing the story and plot to make a statement. I much prefer the first.
The rookie are running a complete subplot on racism and displaying blm cups it's very obvious what they are doing.