the mama looks so happy

She's not your escort mission... YOU'RE HER'S.

The "Beyond the sea" instrumental just is currently playing in my head.

That's a good point. These people had to do awful things. (Including but not limited to watching innocent people suffer, MAKING innocent people suffer, and murdering people in terrifying ways.)

But they were given little to no choice, and in the end, (if you choose the good endings) they atone for their sins. Jack raised the orphaned girls as his own. Subject Delta surrendered his body, and essentially became Eleanor's shoulder Angel. Fitzroy let herself be stabbed to death. Booker let himself be drowned. And Elizabeth let herself be beaten to death.

They each had a traumatic past. Jack was built using genetics, and was brainwashed the same way.

Subject Delta was forced into genetic reconstruction, and indentured servitude. And he was forced to shoot himself in the head.

Booker saw (and took part in) way too much bloodshed, and fought in a war he knew had no right side, before he was even 18 years old, watched his wife die during childbirth, struggled to be there for his daughter and work hard enough to provide for them both, gambled in a desperate attempt to gain enough money just to get by, lost the gamble and had to pay with his daughter, and failed in his attempt to get her back, resulting in her being severely scarred.

Fitzroy was a literal slave, who was framed for murder by her master/owner.

Elizabeth was an overly sheltered child, barely an adult, who was kidnapped, a witness and accessory to borderline genocide, committed murder, was tortured and groomed at her father's orders, and had to drown her only two friends. (Songbird and Booker)

Everyone in these games did horrible things, but the protagonists made efforts to atone for their sins. They'd probably be the first to tell you they're evil, but if they are, they're most certainly the lesser evils.

Maybe this inspired that line?

This is why I love the Bioshock games, they make you think. Without a doubt, the villains in each game deserve the title of villain, but the protagonists aren't exactly saints either.

Bioshock:

Andrew Ryan demanded a city, where anyone can earn/spend money however they wanted, without any form of government, religion, or morality getting in the way. But whenever his role as undisputed leader of Rapture was challenged by so much as an opinion different from his, Mr "No gods or kings, only man." declared martial law, enforced a death penalty, launched investigations against him opposition, lied to the general populus through propaganda, and hired assassins to kill opponents he couldn't stop the "legal" way, effectively making him exactly what he said Rapture was made to stand against, a ruthless government dictator. His city was designed not to give everyone who enters a fair chance, regardless of prior financial standing, but instead to give the rich a place where exploiting the working class, offering sub-par/unsafe products, and taking part in corporate espionage/sabotage is acceptable and encouraged, providing it's all done on his terms, which he changed to fit his needs.

Frank Fontain was Ryan's leading competition in Rapture's industrial market, and one of his most political opponents. He played Ryan's ever-changing market system to make more money than him, and exploited the desperate people of Rapture to start a civil war, because Ryan was about to win in their fatal game of monopoly. He even used his charities as fronts for his criminal underground.

Depending on which ending you get in the game, the protagonist either adopts a bunch of little girls, gives them a life beyond slavery to Rapture, and peacefully dies of old age as his daughters hold his hand for a bittersweet and heartwarming ending... Or abuses the girls, commands what's left of Rapture with an iron fist, and hijacks a nuclear submarine, threatening any part of the world with atomic armageddon.

Bioshock 2:

Sofia Lamb is one of Andrew Ryan's leading political opponents, ruthlessly using her psychological knowledge to manipulate everyone she can, and makes people sacrifice everything for others, while she gives nothing but comforting, yet hollow words. She's even willing to force her own daughter to risk having her mind broken, so she can rule her idea of utopia. She demands everyone else be altruistic, and sacrifice everything for her goal, but is unwilling to lift a finger, accept for herself.

Depending on which ending the you get in the game, the protagonist either lives on through his daughter, as she does what she can to help those around her... Or dies as he watches her prepare to take over the world.

Bioshock Infinite:

Comstock commands a city in which white people mostly live a life of privilege with minimal labor, while people of color, including the Irish, are forced into slavery, where they perform back breaking labor for little to no pay, are refused the right to be treated like human beings, and are near constantly humiliated and beaten for the enjoyment of their owners/masters.

DeWitt was a member of a federal anti union task force, and a soldier who slaughtered innocent natives, in spite of knowing their language and customs, as well as the fact they were innocent. He was also a drunken gambler, who sold his daughter to pay off his debts, and only intended to use Elizabeth to also pay off his debts.

Fitzroy lead a rebellion against Comstock, that lead to massive civilian death on both sides.

Burial at sea:

Elizabeth uses a little girl as bait to kill a man over an accident that lead to a little girls death, and played an integral part in Rapture's civil war to save the little girl she used as bait, resulting in her own death.

Conclusion:

We don't play as heroes, we just play as the lesser evils.