Sensitivity and Boys

My older son is a sensitive soul. He has empathy coming out of his ears for everyone...well maybe everyone but his little brother....
As he gets older I worry how he will cope with the other children disappointing him. I mean we all know that this society is not kind to boys, and I accept that, and I don't want to shelter my boy...but...when he looks up at me with tears in his eyes because a child told him that he has to be the "bad guy" it breaks my heart. (in reference to playing a game of superheros)
And the child is not being malicious, and they don't understand that K is vehemently against "bad guys", and they don't understand that even if he doesn't agree he will go along with it, because he would rather have a playmate than to play alone....
When other children don't want to hug, or kiss, or hold hands...he is upset, and defeated, like he has personally been rejected.
When a child says, "No. I don't want to Play." or "I don't like you." These words pierce his very soul, and as his mother I watch and wait for him to let it slide, but I know it doesn't...so even if I don't want to say anything, I end up making an excuse..."That Child is tired, or hungry, or just plain mean." And I lie to him.
Does this do him a service? I so badly want to scream at the other child, "Look at him! He just wants to play with you, you selfish child." But I know that they are just children, and maybe they just think he is weird for being sensitive.