Clubs and footballers support causes and set up schemes that benefit white working class communities. Free School Meals is an example of that. There are many more.
Why do you think that by taking the knee footballers are telling you the society you live in is wank? It's a very strange reason to boo them. Maybe I'm missing something - have some players or clubs said the society you live in is fucked?
Whilst things have improved, there are still black players experiencing racism. If they're criticised, it should be for their football, not the colour of their skin. Other players and their management team are showing solidarity by taking the knee with them. It really is that simple.
People are more likely to raise awareness about something that personally affects them. Doing so isn't a statement that nobody else matters.