You'll might want to wait for a native speaker of Japanese to answer your question as well, but I think you could say the following instead: :)
I hate seeing people sad
人が悲しんでいるのを見るのが辛い(嫌い)です。
Those people saw a face laughing at their despair
あの人らは、自分の絶望を嘲笑している顔を見ました。