These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
Complete Monster: Copper pulls no punches in showing the gritty, brutal days of Civil War era New York and this is reflected in some of the city's most vile residents.
Winfred "Winnie" Haverford, a pedophile and murderer, kills a 10-year-old girl in the pilot and rapes her corpse, an act that disgusts even the hardened Anti-Hero Kevin Corcoran. Winnie tries to track down the girl's sister, the witness to his crime, with intent of raping and murdering her to. He also visits a brothel to indulge his tastes in little girls. When his own wife discovers what he's done, she happily sells him out to Corcoran.
The Faux Affably Evil counterfeiter Philomen Keating, a ruthless gangster who despises centralized government, takes over a crowded police station full of cops and civilians. He proceeds to torture them physically and psychologically while having fun the entire time. Keating enjoys stripping them of humanity by injuring the police captain and saying anyone can save him, but they'll be injured in turn. When nobody steps up, he cheerfully mocks them on what they really are. He kills more innocent people, and at one point has a captive tenor sing a funeral dirge before slitting his throat in the middle of it just to see what it sounds like. When cornered by the police, Keating takes a little girl hostage with clear intent to kill her whether or not he's granted safe passage out.
The Scrappy: Annie can be a little grating at times with her ungratefulness and manipulative ways.
Squick: The show revels in it. The first episode of season two begins with a deer being shot and gutted, then Eva getting her back sliced open, then getting it graphically sewn shut by Freeman...all in the first six minutes.
While Kennedy's plot to burn New York City may have had some military value to the Confederacy around, say, the First Battle of Bull Run..by the time he plans to launch it, the South has lost the war. Even if he does succeed, the likely Union response will not be surrender, but the "March to the Sea" cranked up to eleven. Furthermore, Robert Morehouse is more than rich enough to buy an exemption..but he went and fought for the Union anyhow. To a competent plotter, that right there should cast some doubt on his "Rebel sympathies".
Elizabeth mistakenly believed the above idiot Kennedy when he said they would only target unpopulated docks and other areas, not hotels filled with people.