USCG isn't part of TSA; they just happen to report to the same cabinet secretary. I'd guess that the boating run-in here was with CBP.
Remember: DHS exists because after 9/11, politicians got a bug up their ass about how many different federal agencies there were with missions that involved interior security, and decided there should be one cabinet-level authority managing all of those functions. It was not a well-thought-out thing; it is literally a meatball of different security, law enforcement, safety, military, and even scientific agencies.
Which makes it an odd subject for directed contempt.
Or maybe that's what the de facto merger of military and CIA is supposed to accomplish.