Feminist international relations theory (specifically about how "war-like" leaders are) is not very compelling. We have historical evidence of a plenty of epic girlboss dictators who murdered their enemies. Indira Gandhi is one of my favorite examples. Fukuyama (yes the end of history guy) argues that in a democracy female voters are less likely to support war compared to men but even that has only shakey statistical evidence, plus the fact (that liberals won't accept) that democracy has never mattered in foreign policy and probably never will barring world revolution.

Other Feminist IR theorists are doing great work though deconstructing the international patriarchy. The "only men can be warmongers" is just a like a pop science thing in the field