The Heroes and Villains in the Boys are manufactured and both exist
In most stories involving superheroes they just exist, often for reasons unknown (or, at least, reasons unknown to humanity). Humanity doesn't have much say in where their powers come from. They are often accompanied by super-villains with similar origins. Sometimes we get a hint of their origin (modern stories tend to give some clues about where their superpowers originate like those in the MCU where many are aliens or for superman, for example). The important point is that their existence has some external cause unrelated to humanity. And many stories seem to assume that the universe has some balance where super villains also arise (and good stores thrive on conflict).
The "heroes" in The Boys are not random, they are created by people for a purpose. Vought has been experimenting with serums used on mothers/children to create a breed of heroes. They do this because it fuels a huge, profitable hero industry. They pretend the heroes are sent from god or some cosmic random process, but that is a lie.
Initially at least they don't need to create super villains (there are plenty of real-world, non-super bad guys to keep the heroes apparently well occupied). Of course the "heroes" are neither very heroic, morally upright or competent. In one sense the 7 are the bad guys (the super villains of any more conventional story). But, as we find out during season 1, Vought does feel the need to create visible super villains to enhance the role of their "heroes" in the fight against terrorism. They use the same technology that created their heroes and give it to terrorists to improve the incentives for the military to incorporate the "heroes" into military action, something they were resisting at the start of the story (Vought also uses blackmail for this goal, but the existence of superpowers villains is a strong extra incentive).
So, yes, super villains do exist in The Boys and they are a part of Vought's plan to make more money from military contracts.