Presumably Google also has to know your contact info in order to know you are authorized to request removal of search results containing it...
It costs them more to do fraud and abuse prevention than to run a customer support system that happens to hook into google3 (because that's what it is - if you click 'remove result' it just puts it in a queue for review. The privacy portal at myactivity.google.com/results-about-you is just a way to check on the status of your removals).