The bolded section is what is relevant. Yes, I can broadcast around the world. Because it crosses state (and even national ones), then federal, and even international regulation makes at least some sense.
In the case of little 5 watt microbroadcasters, I don't really think it does. I have a small TV transmitter that will reach analog sets that are about 500 feet away from the transmitter. I don't think the feds have any business regulating that either. Some regulation is useful, as without it, much of the airways would probably be pretty useless, because you'd have bozos indiscriminately stomping on everyone and preventing the use of most of the spectrum. This could seriously impact people in a negative way, especially in times of a disaster, like a hurricane or something of similar scale where often the only comms in some areas immediately after is radio.
However, just because some regulation makes sense doesn't mean that indiscriminant regulation does, which is sometimes what Fedzilla does, and often times is doing in the case of microbroadcasters.
I won't disagree with that. The station in question is not a microbroadcaster, it's big enough to cover the entire city. And they are stomping on a legitimate licensee, there's a comment just a couple of posts above this about a small station on an adjacent frequency.
Radio broadcasting is a funny thing. In AM radio, you can get atmospherics where a station can skip it's signal way, way past the expected range. I was an announcer/engineer for 15 years, and I've seen some strange things happen that way. Doing licensing state-by-state just isn't feasible, with the exception being the little college 4-watt FM stations. Where I went, we had one of those and also dormitory AM radio stations that could only be received in the dorms.
The concept of "interstate commerce" is highly overused by Fedzilla, but this is one of the few cases that it's proper.