It should be illegal for any company to store my private information like this. The 'anonymous' sharing of my information is easily de-anonymized. Sites asking for your phone number for "security purposes" are a joke.
You just have to accept that absolutely everything you've done online is public information. If it isn't now, it is being stored and future tools / databases will make what is either difficult to access or difficult to interpret very easy to use in the future.
Using phone number as an example of private information is pretty hilarious. Remember when the phone company used to literally print your name and phone number in a book and send it to everyone in your town? Man, their security was terrible!
But it works perfectly fine as a two-factor auth mechanism to prove that whoever setup the account is the same person trying to log into it at some later time.
What private information? If you give a random website your email address or phone number, it's not private anymore and you're the one who released the secret. Unless they promised to keep it private in a legally binding way, in which case, your wish is already true.
You just have to accept that absolutely everything you've done online is public information. If it isn't now, it is being stored and future tools / databases will make what is either difficult to access or difficult to interpret very easy to use in the future.