They did write about the military angle in the article. It seems they saw it and either weren't paying attention or didn't bother to do anything. I guess it would be kind of a pain in the ass for a military primary radar to attempt to correlate every contact with known flights operating normally and to send up interceptors for anything that didn't seem to match. It's not clear if they would even have interceptors at a sufficient readiness level to actually catch a jetliner at cruising speed and altitude near the edge of their coverage.