Despite its title, the poem doesn't argue against hate so much as try to understand where it comes from. The opening claims that hate "makes a great deal of hot work," as if it were a busy, sweaty trade. The next lines suggest who does that work: men who don't cry, who are angry at being "nobody." Hate, here, looks like grief and humiliation that have been bottled up and turned into aggression.
The last stanza turns inward. The speaker's mind is "in a safe," locked away through "some bargain with doubt." That could mean the speaker protects their thinking by staying uncertain, refusing the hard certainty that fuels hatred. It could also hint at a kind of self-protection that has its own cost. The poem doesn't settle this.
The mood is cool, wary and compressed. Short lines and flat statements keep the tone quiet, which makes the heat of the first line stand out all the more.