Lets have a fictional person called Phil (a victim) and Bob (the guy posting the info) for the purpose of this post.
If Bob posts Phil's name, address, and phone number in a message board without Phil's permission, there is most likely some kind of hostile intent. This usually happens when Phil has managed to make Bob angry for some stupid reason (flame war, abortion debate, maybe Phil is just being a jackass here. Who knows? The reason is not relevant). So Bob gets Phil's info and posts it online in that message board. Why does Bob do this?
Most likely, Bob is hoping someone will go to Phil's house and beat him up. Or break a few windows. Maybe Bob just wants someone to take a crap in a paper bag, light it on fire, and throw it on Phils porch. The intent is to make it easy for all of Phils enemies to harass or inflict harm on Phil.
Target or Walmart do not have any hostile intent. They just want to sell you stuff. They gather and analyze data, and the only objective harm thaty they would intentionally cause is filling your mail box with unwanted spam. I would agree that doing so should earn someone a kick in the nuts anyway, but it is only annoying, not dangerous. In many cases they are using info they gathered themselves for their own benefit. It could also be argued that what they are doing is of mutual benefit: Walmart gets Phil to buy stuff, Phil will have a chance to buy something he wants.
The only problem for Phil is when access to that data is then sold, shared , or illegally accessed by those whose interests may run against him. There needs to be legal protections in place for Phil, and Walmart needs to be held responsible for any harm that comes of them keeping that database.
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