In the immediate aftermath, utter chaos. Bloodshed and global riots. A temporary breakdown of global communication infrastructure is to be expected. Small chance it becomes permanent.
After this, after the grieving for half a world is done, a natural experiment is run to test the theory that the world wouldn't be so awful if it wasn't run by men. They find that it remains awful, but the awfulness is slightly different qualitatively. Humans are humans, biological sex changes less than most think.
In the long term, the result will be either a gradual extinction over the next eighty years or so, or the development of human parthenogenesis technology. No "real" men will ever be seen again presuming all genetic information is destroyed. If it isn't, men might reappear from taking Y chomosomes from male remains that were already dead when ROB murdererd 3,500,000 people by deleting them from reality. That said, given the cultural shifts I've been observing over the past decade, and the power of Us vs. Them (Ingroup/Outgroup) thought in an all-female world where men are the ultimate Other, I doubt men would ever make a serious comeback, save as tightly controlled research subjects.
I'm not sure what's funny about any of that.
Switch this scenario so ROB commits gendercide against women, humanity still probably goes extinct with slightly higher probability. Artificial wombs are probably harder to develop than the technologies women would have to create. It's probably slightly more likely women get mass revived; mainly because it's easier to do so, and harder to control. All men gone? Y chromosomes are some of the rarest molecules in the world. All women gone? X chromosomes are still dirt common.
If all male organisms are gone - not just human males - multicelluar life other than tardigrades dies. Tardigrades are all-female.
