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.
So what is the strategy to build a vanguard? The mutual aid is just a way to attract people to the movement, sure, but it's the best method of attraction there is.
Protests are good for agitation but the christofascists have so many well established, well funded churches any revolution would immediately be taken over.
The problem is a lot of the groups who do mutual aid in the US are also ideologically opposed to forming centralized vanguard parties.