it is probably the case that a lot of people have the concepts of solidarity and sacrifice intertwined with each other, for the reason that they interpret the world through a religious filter.

when you don't see the world through the filter of a religion because you could never be bothered with it, these ideas are not just separate but largely contradictory. solidarity is mutual aid, which is about advancing shared self-interests - it has nothing to do with sacrificing for others, which is just flat out irrational.

it's important to recognize these linguistic and conceptual subtleties when dealing with the left, which is starkly irreligious. we may perhaps use some of the same words, but they don't always mean the same thing to leftists that they do to religionists.