The speaker's attitude is set up from the very first lines of the poem in which an implied metaphor likens society to a "bloodsucking bat." This is followed by a subjective explanation for this extremely negative attitude when the speaker lists the fears driving the attitude:
I fear that the human race may with tall walls wall me, with strong drugs dope me, with wise lies lure me,
Since these expressions and fears are coming from one yet unborn, the negative attitude is heightened and dramatized because it is antithetical to the traditional expectation of an unborn baby's attitude toward the life and society that awaits: the expected attitude is innocence, joy, and expectation of good.
The speaker's negative attitude of fear and repulsion is further explained with more detail later in the poem (e.g., "rehearse me / In the parts I must play ...") and is summarized in this line:
O fill me
With strength against those who would freeze my humanity,
The speaker's attitude toward society--one that expects the worst kinds of treatment and is summarized in the line above--explains the meaning of the concluding lines that equate loss of humanity, through another implied metaphor, with becoming stone; with life being spilled; and with what might be called living death:
Let them not make me a stone and let them not spill me.
Otherwise kill me.