Is this legal? Did they even read the TOS for Google?
Do people think companies that deal with PHI have to build every service in house...? Run their own data centers? Build their own backhaul connections to their users?
Obviously I don't have a copy of the contract between Google and Oscar, but I think it's profoundly unlikely that they would write a blog post about something that would be the end of their company without the "simple" (and industry standard) step of signing a BAA with a vendor.
That's...encouraging.