各位好，
Heartless human beings are like wild animals, which rip their own kin in the slightest of need and that too without a sign of remorse.
①这里that语义上应该是指代human beings对吗？可是不应该用those吗？
②就算是用了those，too的作用又是什么呢？中间省略了什么呢？
感谢各位的解答！