The logic is somewhat amongst these lines: the red-ish girl has only a few friends but they cry at her grave so apparently they are true friends whilst the blue-ish girl has plenty of ''friends'' who didn't bother to even bring a candle to her final resting place.
As a person who couldn't give less fuck about my grave and funeral, I don't really think this logic is of any use.
I think it's just a representation that they really cared. I'd rather have two friends who will always be there for me and vice versa than have ten friends who I can't ever count on.
I never really cared about how close people are to me and basically treat everyone the same. If you show me respect as a friend, your good enough for me to talk and interact with. I'll invite you to places if I get a chance to, even if we just met yesterday.
As a person who couldn't give less fuck about my grave and funeral, I don't really think this logic is of any use.