The TSA's response here is childish and embarrassing, although perhaps unsurprising given the TSA's institutional disinterest in actual security. It's interesting to see that DHS seemingly (initially) handled the report promptly and professionally, but then failed to maintain top-level authority over the fix and disclosure process.
What was surprising to me was that they didn't immediately do pre-dawn raids on the pentesters' homes and hold them without a lawyer under some provision of an anti-terror law.
(It's very easy to believe the worst possible thing about every corner of our government, since every corner of our government has something bad about it. But it's a fundamental error to think that every bad thing is always present in every interaction.)