It's the easiest thing in the world for the giver, but to the receiver it feels like a kick in the gut. It definitely contributes to the feeling of hostility.
I have several well recived answers there but I have never downvoted anyone because leaving it as is feels right than downvoting for the reasons you mentioned. I never asked a question there and tried figuring out the answers based on existing resources and on my own and it helped me learning a lot. This might not be the right way but being hostile and downvoting feels more than disagreement to me. This is the reason why I avoid being there.