The federal government in the US has pretty strict regulations with regards to PII (personally identifiable information). But apparently Florida doesn’t.
The USPS makes only a few million from selling this data but saves over a billion dollars by avoiding the cost of forwarding mail sent to prior addresses.
The USPS is allowed to do this under an exception for it in the Privacy Act.
If you were renting it's possible your landlord or management company provides information on new residents for 'cost saving offers'.