Why didn't the White House use WordPress for healthcare.gov?

Article feels slightly silly, like looking at a collapsed building and asking why they didn't use a better interior designer.

IIRC from past HN threads, the vast majority of the CGI Federal contract cost was on the business logic (the "data hub" backend which had to integrate with about 50 (!) existing databases, the 34 FFEs, and so on). "Just use wordpress" isn't really a sensible answer.