it's +adj for sb to do
此处的for 表示 对于某人来说.
it's +adj of sb to do
of 表示某人自身的特点,故可以换成
sb is adj to do
比如：it‘s nice of you to help me.=
you are nice to help me.
it's wrong of you to do sth=
you are wrong to do sth.
it's wrong for you to do sth
表示 做了那件事 对你 是错的.
两种结构都对,意思有偏差.