That's not what was happening there. They weren't hiding the identity, it's that they had not positively identified the victims. The cops talked to journalists very fast.

They hadn't positively identified them, but they knew exactly how old they were?

It seems much more likely that they had identified them, but they hadn't gone through the full set of procedures (notifying family members, etc.) that are required before officially releasing names.

If that's the case, that's really just dumb side-skirting of compliance rules, how much difference does it make for a yet-notified family member to read "Persons aged [dad's age] and [mom's age] found dead at residence of [their last name]" compared to "Mr. and Mrs. [their last name] found dead."?

In any case, tragically, their daughter lived across the street and found them.