but I am pretty sure he owns (or used to own until recently) a lot of bitcoins.
He bought an insignificant sum on mtgox in 2013. There is no evidence that I'm aware of to suggest that he had any when he started scamming Bitcoiners. And there is a lot of evidence he didn't: If he did, why would he be risking them (and his freedom) attempting to defraud the AU government for millions? Why, when the AU government caught him and demanded he prove he had owned bitcoins under risk of imprisonment (his scam required him to claim to have a lot of BTC) -- didn't he reveal some of them instead of taking the risky step of claiming that a bunch of MTGox's coins were his?
He wouldn't have been sued for billions unless people new he had them, no?
The people suing him are doing it just on the basis of his public claims. For them it's a simple strategy: Either Wright is telling the truth and they're owed big time, or Wright is lying and he should settle with them (for, say, a few million) quickly before their discovery process reveals more of his criminal fraud. Win/win. To do this they have to treat his public claims as the truth, even if they don't believe them. Though they might... filing a lawsuit doesn't give them any special insight. The fact that wright is frauding is better for their lawsuit since it creates more incentive for wright to settle quickly. (Unfortunately for them, he's just not that sane...)