Oracle is already close to being classified as junk and reaching a tipping point. If/when that happens it is unclear what affect that will have on the markets on companies invested in AI datacenters with Oracle, and other companies that Larry Ellison and other Oracle investors own shares in.
So the worry is that it makes it clear that the unexamined risk in the SPVs has a lot less light shed on it.
(ETA: that article suggests Oracle is using SPVs)
I mean yes, there are key contractors for certian things, but depending on the structure they can be chapter 11'd to yeet that debt.
Of course junking all those bonds would cause a crisis.