If you use the platform, you've expressly agreed to this behavior. You can't create an account without affirming that you read and agreed to their policies and terms of use.
>We call all of the things you can do on our Products "activity." We collect your activity across our Products and information you provide, such as: [...] Apps and features you use, and what actions you take in them.
>We collect information when you create an account or use the Platform. We also collect information you share with us from third-party social network providers, and technical and behavioral information about your use of the Platform. [...]
>We may collect information about you from third-party services, such as advertising partners, data providers, and analytics providers.
Instagram's privacy policy: https://privacycenter.instagram.com/policy/
>We call all of the things you can do on our Products "activity." We collect your activity across our Products and information you provide, such as: [...] Apps and features you use, and what actions you take in them.
Tiktok's USA privacy policy: https://www.tiktok.com/legal/privacy-policy-us
>We collect information when you create an account or use the Platform. We also collect information you share with us from third-party social network providers, and technical and behavioral information about your use of the Platform. [...]
>We may collect information about you from third-party services, such as advertising partners, data providers, and analytics providers.
Aren't EULAs fun?