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.
I'm not here to point out a specific point of delineation; a mound of sand is not a few grains of sand even if the point where it becomes a mound is undefined. The important thing is to work to understand the structural forces on different segments of society. If the proletariat is just the proletariat, where do reactionaries arise? Where does the tendency to social chauvinism?
You correctly point out that white-collar workers are under a greater or lesser degree of exploitation at different times. Now as the empire weakens, they are going to be squeezed more. There interests vacillate but you can't see and act on that by sticking your head in the sand and declaring all workers are equivalent.
I have yet to see a revolutionary organization in my city that is not terminally white and from a substantially different labor background than the people in my city. That gap does not exist for no reason! As marxists, we must examine the problem and work to solve it. We must build a movement of the broad masses and not just the intelligentsia.