By the time a noticeable subset of your users are doing things your investors/advertisers/hosting providers/app stores/mother would consider "deplorable", it's _way_ too late to be thinking "Yeah, maybe we should have built in some protection for ordinary users against griefers/trolls/russian and chinese misinformation campaigns."
I'm not saying they need to do it right now, or that it's a more important thing than gaining users/traction right now, but it should without doubt be a thing that's very near the top of their list of "things we have considered and have vague plans to implement, that need to watch carefully for, and to have not painted ourselves into corners where our ideas about what we'll need to do to stamp it out no longer work any more..."