Are you saying that streets with these words painted on them are closed to traffic? Just do an image search for "Black Lives Natter Street Murals" - see if you find any photos or videos of traffic moving freely over the "murals".
I haven't seen one photo or video with vehicle traffic running on a mural but I do see streets, traffic lanes and murals blocked off with traffic cones and barriers.
Also there are various stories describing how traffic has been blocked from the mural streets in different cities.
If the blocks with the street paintings are closed to traffic, that would mean that the stores and people who live there would not have normal access to the front doors of their buildings.
We are living in perilous times. I never thought I would live to see the day when mayors and governors would be taking actions meant to worsen the economic and safety levels of their own people.