I think the Onion writer has an outdated idea of what the US Coast Guard does and doesn't do, and that the reality is closer to the Onion story than the writer realizes. The USCG isn't in the business of doing routine tows when there is no imminent danger to a vessel or people on board or other waterway users, but rather lets commercial towers do the work. But it sounds as though the Onion writer is trying to parody an era of USCG towing service that has long since expired.
What's truly unfunny is that I saw this on a post on FaceBook and someone actually thought it was a true situation. Kinda like when Congress got bamboozled by an Onion article not too long ago...stuff happens, ya know, and if it's posted on the internet, then it must be true.