From Teflpedia

Man is an English noun with several unusual properties.

Firstly, it is one of the most common words in English. Secondly, it has an irregular plural "men". Thirdly, it marks grammatical gender, in this case masculine, so is not gender neutral language. It forms a masculine-feminine pair with "woman".

Man forms a number of compound nouns, e.g. fireman, postman, etc. Also, manpower, manspreading, mansplaining, etc. These tend not to be gender neutral. In some circumstances for some meanings gender neutral language may be preferred.