______you don't like him is none of my business 为什么用That 而不用whether

用that,句意是 你不喜欢他,这不关我事.
That you don't like him is none of my business .句中is是谓语,整个句子是主语从句.从句中you don't like him 表达完整,内容结构都不缺,而主语从句不可省略引导词,于是我们用毫无意义的that来引导该从句.whether 在从句中,有“是否”的意思,此时便不合要求.
要用whether,则句子改成：
Whether you like him or not is none of my business.你是否喜欢他,这不关我事.whether不可以加否定的句子吗？恩，不加。加了之后句子就会有冲突了。