[Anechoic]

Also interesting things like Whiteman AFB, from the recent stealth bomber post, shows nothing

Those maps are generated by publicly available data (traffic, railway schedules, etc). In the case of airports/airbases, the data are generated with radar flight tracks. Military flight track data are often redacted (presumably because they can leak aircraft performance data) so it's not surprising that modeled noise from stealth aircraft was not calculated.