There is no doubt that humans are shitty. Was that ever in question? The #metoo movement has brought forward, and into public discourse, a problem. Had this not been brought forward even Argento's indiscretions wouldn't be known. The things highlighted by the #metoo movement are impactful and important to the advancement of our society and civilization. These actions should not be considered "OKAY" and most people who say the #metoo movement is filled with witch hunting and should be stopped are effectively discounting any of its gains. Nothing is perfect, but we can all strive to be better—and maybe with #metoo visible in the world we can avoid the problems of the past in our future.

I believe the other two persons arguing with you here are simply saying that #metoo has a noble agenda but was quickly hijacked to push other people's agendas. Which is sadly a pretty classic scenario IMO.