I don't like the TSA any more than you do, but can we hold on to the Coast Guard?
Same with most of what you mentioned. Bush/Obama has shoved everything in there to create a psuedo military branch so it can't be declined in the future. Disgusting actions, honestly.
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.
Completely unrelated agencies having to carry the ill will engendered by the ones that suck is one of those costs.
Perhaps they should have considered that.