YABU!
The whole point of blue (and other coloured) plaques has always been to remember significant people and important events from the past. This one isn't the only one that commemorates an unhappy historical event or tragedy of some kind. There are plenty in London like that too.
Choosing who gets remembered, and what they are remembered for - along with who gets forgotten - is an intrinsically political decision, and always has been.
Personally, I think it's important that we remember people like Oluwale. The fact that his was the first time that British police officers were actually prosecuted for their involvement in a racist killing is extremely historically important. But then I would call myself an 'activist' and have actually been involved in putting up plaques.
What is even more shocking is that over half a century later, British police officers continue to kill (mostly black) people with absolute impunity - it's estimated that several thousand people have died in custody/ at the hands of the police in the last 40 years - Chris Kaba is just the latest case to hit the headlines. <see www.inquest.org.uk/deaths-in-police-custody if you want statistics and www.inquest.org.uk/family-campaigns for more info about various families' campaigns for justice>
Perhaps if plaques were erected for each and every one of them, it would be obvious how many lives were being lost and increased public awareness/outrage might actually lead to some change in society....
I really hope posters like @Suetwo mean the police when they refer to "bullies" rather than referring to bereaved families and friends, and other anti-racist campaigners as "fanatics".