Fair enough, but I can't see how I "twisted it a little bit".
I don't see how any reasonable reader can interpret "Fanduel is gonna lose this one" as anything other than they pay the full ticket price.
There has absolutely been a PR hit, already, because most stories and lots of comments (like yours!) have implied FanDuel is in the wrong, and disliked for their behavior. (Even if it's a negligible effect among significant gamblers, it's not good for their brand among casual and new players. I had no idea they were operating actual betting windows, as opposed to online real-money "contests", so I've lowered my estimation of FanDuel from "novel online innovator" to "same old casino sportsbook".)
And further, if Fanduel were to confidently say they wouldn't pay, and then "lose" in a legal action as you predicted, there'd be deeper hits. First, a second round of stories that "Fanduel loses". Then, many more gamblers emboldened, in future similar situations, to insist on payment-of-errors rather than accepting the casino's "house rules".
And I believe definitionally, there are no "FanDuel loses but the bettor does not get anything meaningful" paths. If the bettor "doesn't get anything meaningful", for whatever reason
– including that the rules are murky enough the bettor gives up, or the courts/regulators are stacked against such complaints – then those are precisely "FanDuel wins" paths. As I'm predicting, and willing to bet on, while you're predicting they "lose".