There is a significant piece of FCC law that makes it illegal to re broadcast some classes of monitored communications. Internet could easily be seen as a re broadcast medium. NPS may have gotten after the guy because one of the things that can't be re-broadcast is emergency and public services type of com. YOU can listen in, but not re broadcast. At least that is what I remember from many years ago as I was getting a commercial radio and amateur radio operators licenses.
pw, You may be right about the legality, but, check the web page for broadcastify.com. They claim 5,000 feeds. Not all police/fire/ems, but I'd think if there were (or had ever been) a problem, there would be all kinds of legalese on the home page.