The Panthers did free before school breakfast and after school babysitting and all sorts of actual community building like that. The PSL does protests and craft events and that’s it. I guess providing consistent services is an order of magnitude more difficult than organizing marches but it just doesn’t seem like the marches are getting us anywhere.
What do you mean by the Marxist conception? Marx himself sometimes uses the term middle class.
Here’s a few examples.
The Communist Manifesto, Chapter 1:
The 18th Brumaire of Louis Bonaparte, Chapter 1:
Capital Volume 1, Chapter 25, Section 4: