Large platforms such as Facebook (including their Messenger Kids service), TikTok, YouTube and many others routinely and willfully violate child privacy and advertising laws, develop and operate platforms with addiction-forming UX patterns, and datamine and track any of it's users into intimate depths of behavioral and personal information, including biometrics like facial recognition data and much, much more.
When you provide parental consent to these platforms for your children, you are agreeing to their Privacy Policy and other legal agreements which only given them further legal protection to continue performing these types of activities, depending on the nature of the agreements.
The Children's Online Privacy Protection Act (COPPA) prohibits websites and other online platforms from collecting data on children under the age of 13, unless parental consent is provided to allow them to conduct these practices.
Despite having legal and financial ramifications for violating the law, these platforms routinely engage in such activities anyway, with some exhibits including:
Many other examples of COPPA as well as GDPR (respective to EU) violations can be found at this summary
The solution to this problem is through small, accountable, locally-operated platforms, including self-hosted options where families can have more autonomy and control over their digital presence, and not be cornered into using platforms with predatory practices.
Through the use of federated protocols, families and individuals can run their own platform, while still be able to intercommunicate with other alike platforms, rather than playing into the exclusivity network effect of platforms like Facebook, Instagram, YouTube, etc.