@ToffeeYoghurt
You don’t seem to have read my post properly.
The risk of dying at the hands of the police from being a black man in the USA is much higher than the risk of dying from CV19 - whatever age/race you are.
So the people protesting are, quite rightly IMO, making a stand against the greater threat to their fellow man.
How does it help? It shows solidarity, brother/sisterhood, provides evidence of a larger body of public support, it helps people voice their anger, it garners headlines and other media coverage that reaches more people and encourages them to examine the systemic failures in all our countries to protect and further equality amongst all races.
You talk about risk without seeming to be able to evaluate that risk in a meaningful way.
For your scenario (whereby the protestors are endangering BAME lives across London - to paraphrase) to be true, one or more protestors would have to be: infected + shedding + not wearing a mask + stay within 2m of someone else for 10/15 minutes or more. The other person would also have to be close enough for long enough for enough viral particles to enter their body by way of soft tissue such as eyes.
A lot of different criteria need to be met for each potential transmission - a lot more criteria than needs to be met by a black man living in America to die at the hands of the police. All he has to do is exist.
And before you ask why protest in London when I’m giving the example of an American black man - because I don’t think British lives are more important than American ones; if people want to stand up to be counted here, in solidarity with Americans, then that is their right.