It's extremely easy to remain anonymous under a username and picture that won't be associated with your offline identity. You don't need the advantages that come with not being subject to a registration process, and that prevent us (moderators) from carrying out our job efficiently. Don't want to face the backlash that might come with expressing unpopular opinions? Use a throwaway account.
We may eventually become desensitized to violent & graphic contents, sadism, attacks and hate speech when they get too common. This may make many people more resilient in real life.
How is that a good idea? A resilient person isn't one who cannot feel or respond normally to negative stimuli but one who can take enormous amounts of pain and bounce back seamlessly. You don't build resilient individuals by turning them into cold-hearted apathetic beasts, you do so by giving them the tools they need to heal.