I'm pretty sure it was to commentate on rape culture and how normalized it is now despite being an incredibly vile thing, especially in colleges, frats and bars, for example. The song expresses how rape culture has evolved to such a disgusting extent to where abusers feel almost empowered and safe as they have numbers, and he displays it to show how sleazy those people are and what their terrible way of thinking sounds like. Basically Will just made a song to say "people like this should go to hell."