It was true up until 2007, but is currently not the case.
When LPFM was originally created in 2000, the thought was that national non-profit organizations would be obtaining licenses and that there would be more periodic filing windows. So as a result, the FCC enacted a rule that allowed a licensee to own up to 10 LPFM stations with a restriction that no two stations are less than 12 kilometers or 7 miles from each other. In order to assure localism, the FCC gave a "head start" in the first window by limiting organizations to one station. The thought process was that the FCC would follow up with a second window to allow organizations to pick up additional stations.
Because of advocacy efforts and due to the outcome of the 2003 "Great Translator Invasion" window, the FCC made a change in the Third Report and Order, released in 2007 that changed the ownership limit to one station for most licensees.
Public and private sector organizations that have a contract, compact or memorandum of understanding with a state, county or municipal agency to provide public safety services may own multiple stations within the jurisdiction that they operate in.
In 2012, with the Sixth Report and Order, federally recognized Indian tribes/native nations may own up to two LPFM stations in order to serve tribal lands.