This happens when your data has been given out freely by some ICO's who collected your data maybe for some KYC purposes. But also people do get our info and use it as theirs and at the end our info has been submitted
Yes, you are right that's why we have to be very careful when dealing with the ICO because some fake companies will start collecting data, sharing those data to unknown users which will harm us because sharing those will leads to scam the people.