A woman like that is not a woman, quite. (6)
What is it that makes someone a woman, exactly? Stating that our speaker is an outsider allows Sexton to trouble the assumption that "women" are all the same.
A woman like that is misunderstood. (13)
Notice something funny about these lines? Our speaker doesn't say a "woman like me." Nope, it's a woman "like that." It's almost like she's turning the lines before this one into a case study: here's one example of a woman. And here's another. Notice how they all seem to be ostracized? Hmm...
A woman like that is not ashamed to die. (20)
Sexton turns gender into a battleground – one where women are persecuted for…what, exactly? Well, that's part of the power of her statements. Because she never specifies exactly why she's being persecuted, we're left to assume that it's just because she happens to be a woman.