I think it's a bit of a stretch to say every online game ever, not all exploits found are equally broken.
That said, this isn't the first time I've seen this situation. I doubt most here have played the original Phantasy Star Online for the Dreamcast, but that had rampant duping to the point it really did essentially ruin a lot of the online, mostly because of a weapon called the Spread Needle. It was this rifle that had the spread of a shotgun, but the fire-rate of a rifle, and it fired thousands of these little needles that did a ton of damage and also paralyzed (which essentially stopped enemies completely.). People would join your room with that stupid over-duped gun and essentially clear entire rooms of monsters by just standing at the door and firing in its remote direction. It got so bad that many including myself would just leave the room immediately the moment a spread-jerk would enter the room. Later versions fixed it, but that kinda cemented my view of duping in an online game forever.
It's not as bad as that in this game quite yet, although earlier was in a game where some tryhard came in talking like some experienced seen-it-all veteran, and when we fought Saturn to do the data mining quest he just did that half yawn tone and busted out his bee+cc like "don't worry guys I'll take care of it".
I've only seen one "debatable" case of cheating online. Only one. Some zero was using a shotgun with what seemed like a million pellets as the entire enviroment got cluttered for a half second every time he shot it I thought maybe t was just a render glitch until I saw that it was coming from his gun and eating an eighth of bunkers health each shot while he was under leveled in TVHM. I just kicked him.
As far as the co-op argument goes I remember in mass effect 3 when players were glitching people cried about it until it was fixed and that was co-op. Cheating is cheating whether it's competitive or not.