To add on to what others say, not only are children naive, but you have consider pedophiles as adversaries not unlike you would consider a skilled hacker. Just like a hacker may set up an entire company page and prepare a series a mock interviews just to get a senior engineer to open a malicious PDF; so will pedophiles who target children online. They don't wear an "I'm a pedophile badge", it starts with a slow build of confidence and trust that someone without experience will be vulnerable to.
Also the kind of damage they make is worse. Companies can be rebuilt, money can be regained. Pedophiles start at “infancy trauma for your child” and goes up. As a parent, I would cut my own hand in order to spare my child from that. This is not an exaggeration.
This. The network of lies may be intricate. The child may believe to be interacting with someone their age that they come to consider their best friend.
Think of the elaborate long-term deception that can be involved in regular heterosexual marriages. Some people have multiple families that don’t know about each other! Now consider what it can be like if that same dark energy is applied to lying to a child online.