So the reason that the attorney general of New York actually served DraftKings and FanDuel with cease and desist orders is because the state claims that it is just a thinly veiled type of gambling. They assert that there isn't really any skill involved and it is more random chance that leads to winning, which is essentially gambling. And, of course, gambling is illegal in the state of New York, meaning these companies would not be able to operate there. They would lose out on a big chunk of revenue, and set precedence for other states to ban them as well.
Honestly I tend to agree with the state of New York on this matter, as I have actually checked these websites out it really is nothing but a glorified type of gambling. They use manipulative advertising to lure players into thinking that it is a game of skill, when it is essentially impossible to predict how each player will do each week.