Like most jokes, portmanbros began as larks—“brodown,” “bromance”—but can now be a bit more pointedly political.
2014, Stephen Marche, "On 'Bro': The Use And Abuse Of A Loaded Word", Esquire, September 2014, page 107:
Among writers who are trying to be funny, the word has morphed into a series of fused words—comic portmanteaus (portmanbros, if you insist) that have launched a full-on brocabulary: brogrammers, for young male computer programmers; […]
