I am not certain that there is anything particular direct in Sylvia Plath's poetry. The anger, perhaps, might be the only element. Yet, I think that outside of this, there is so much in way of ambiguity in her poetry that so many doors of perception can be left open. It is this that makes her poetry so strong and powerful. I think that this is where we are in the gender of the character in "The Applicant." Plath is able to construct a reality where it is evident that there is an objectification for a spouse present. This seems to fit well with describing a woman who is being sought for an alliance of marriage. Consider the opening stanza in which the objectification of a woman seems to be consistent with what is being offered. "Are you our sort of person" helps to bring out how women were seen as having to conform to the standards of the prospective in- laws. The physical objectification of "scars" and "rubber breasts or a rubber crotch" continues this objectification that seems to be suggest a woman being the subject of such scrutiny. The refrain of "Will you marry it" also seems to be a question being asked of a man about a woman. The descriptors of the domestic notion of woman helps to continue this idea that a woman is the subject of the description.
Yet, I would bring out the idea that I think the poem can talk about any individual who is forced to conform to a standard that is not necessarily representative of their own wishes. In this light, the poem's subject can be a man or a woman who is forced to conform and appropriate a standard that is not theirs to own or to represent. I think that this becomes an element where the poem's subject or character simply revolves around the suffering imposed on the outside world upon an individual who simply lives to live a life that is not in accordance with the social norm of expectation.