I'm sure there is a simple answer to this, but after some googling I haven't really found any clear answers (or at least answers I understand). From my understanding 'otoko' means 'man/male', and 'onna' means 'woman/female'. Yet for some reason I've mostly seen the phrases 'otoko no hito' (male person/man person) and 'onna no hito' (woman person/female person) to refer to men or women respectively. One such example is the line "Sara wa otoko no hito ga kirai desu." (Sarah doesn't like men). Why is it that we need to add the 'no hito' (if I understand correctly 'hito' means 'person'), to 'otoko' and onna. Wouldn't it just be easier to write/say "Sara wa otoko ga kirai desu.". Does this have something to do with context or formality?
Note: I'm still very much in the beginner phases of learning.