Part of why we say "solidarity not charity" is because the way charity is typically presented gives moral superiority to the givers - and often, moral inferiority to the receivers (or sometimes "takers," if they decide to be particularly transparent about it)
Truisms like "it is better to give than to receive" implicitly contain "it is wrong to receive help." It's wrong to ask for the support you need, to want it, even to accept it when offered. Panhandling, for instance, is often portrayed not just as shameful, but immoral - even greedy
Solidarity, and especially mutual aid, are meant to reject that dichotomy. Everyone at Food Not Bombs eats together, volunteers and otherwise, and talks to each other. Our Free Store puts "it's free because it's yours" all over its reading material - it's not a gift, not a blessing, not charity. And that makes *such* a big difference