Certainly, there are people who give generously to charities and worthwhile causes who don't know God. Do they not make a difference in others' lives? Of course, they do.
This verse is saying that, if we do not know God's love, it doesn't matter what we do. We could give away everything we own and die for a cause, but where does that get us? It does not impress God. It does not give you any brownie points.
I pray that you experience God's wonderful, expansive, never-ending love.