Corporate personhood protects shareholders from liability for corporate debt. If you were to become part owner of a non-incorporated company, and that company went bankrupt, you would be liable to pay off the company's debt that you probably had nothing to do with. When a corporation goes bankrupt, its shareholders (part owners), being separate legal entities, only lose the money that they have invested in the corporation. Corporate personhood does not protect white collar criminals from prosecution. If an accountant commits tax fraud, they, not the corporation that they work for, are guilty.
Corporate personhood protects its shareholders from corporate debt. For example, if you were to invest in a non-incorporated company and become part owner, and that company got sued, you would be personally liable to pay off the company's debt that you likely had nothing to do with. Treating corporations as a separate legal entity protects shareholders from personal liability. If Pepsi goes bankrupt, the shareholders, being separate legal entities, only lose the money they have invested. Corporate personhood does not protect white collar criminals from being prosecuted. If someone working for a corporation commits tax fraud, they, not the corporation, are liable.
This only came into place to make employees not responsible for their immoral actions. If they broke the law or victimized someone it is because their vague idea of a personhood-wielding-all-holy-company made them. We let white collar crime slide by creating a tricky system of legal hijinks instead of calling it what it is - bullying.