The issue of gender arises in "No Second Troy" through the comparison between Maud Gonne and Helen of Troy. We don't want to oversimplify Yeats's thoughts on women. Yes, he had a conservative personality, but he was also attracted to strong, intelligent, powerful women like Maud Gonne. Gonne sounds like she was every bit Yeats's equal. But the speaker of this poem also falls for the story that Helen of Troy, that beautiful temptress, caused the Trojan War all by herself. The poem presents feminine beauty as powerful, dangerous, and potentially manipulative.
The imagery in the poem overreaches in trying to make the case that Maud Gonne has an inherently violent character.
In arguing that Helen burned Troy, Yeats lessens the responsibility of men. In this poem, men lose their status as independent agents in the presence of powerful women.