Earlier quoted context omitted.
There are genuine privacy concerns at play here, for example there may be existing tenants/owners who don't want people randomly knocking on the door because someone saw an ad online. Or getting a bunch of junk mail because there is an extra data point about the property. I guess the variety of concerns will vary from country to country depending on local laws / existing open data though.
I don't think it is reasonable to expect to be able to list real estate for rent or sale, and also expect privacy with regards to the address.
The owner doesn't really have a reason to care, I don't think, and may even be incentivized in some situations to reveal information the tenants would rather they not.