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 mean if you know why the Panthers did provide school breakfasts, you're probably aware that it's more than a matter of simple organisation. The American state has nearly a century of practice crushing leftist movements, so just going out and doing something to make the world a better place will paint a target on your back.
On top of that, mainstream media doesn't report it. Even when things do get off the ground, they're either incredibly local and won't turn up in national news, or will be explicitly ignored by the media because of their leftist roots. Protests are big and disruptive enough - and involve specific press releases about the event - that they usually have to be reported on, even if it's negatively, so you hear about them in a way you'll never hear about mutual aid programs.