These are called shrink wrap laws. You have to purchase the game an open it in order to read the TOS or the EULA, 99% of the time nullifying a return.

Dude I just pulled that off activisions website without buying anything. And shrink wrap laws would be because you bought the content from a store, that's not something Bungie can help. Even if you buy a disc at a store then youd still have to agree before you play the game, AND it's still public for those who want to read it. Bungie doesn't conceal it from anyone. Regardless, if you bought the content then you've agreed to these terms and conditions and are held responsible for them, if people don't like the DLC content then they should have though about that before they bought it.

How would you know about that TOS/EULA before you bought the game if you just bought the game on a whim and had no account here?

Haha I'm gonna bet that Bungie doesn't give two shits if you buy the disc or not (in a legal sense) before you can access their content you have to agree to the terms of service, and like their terms of service said you are buying the LICENSE to play the game. Just by buying a DLC code, you still have to agree to the terms of service before you can download it to your account and implement it. Either way, whether you read it or not you accept the terms of service before you access the content. Besides that, I'm just some dude on the Internet advocating that, if Bungie or activision put a legal team in any lawyer giving that defense would have a shit time competing with it. Bottom line: you agreed to the terms of service before they let you activate your license in their product, and everyone who bought and played destiny had access to, agreed upon, and "honored" the terms of service before they could create their characters. That's how it is, or would you prefer to be required to read and sign the terms of service before you buy a game from Walmart or GameStop?