Many government systems can be replaced by modern upgrades with zero incremental spectrum footprint above the commercial and private systems on which the highly productive civilian sector depends. Look at FirstNet.
It goes without saying that US regulatory performance on the 5G mid-band and aviation is well below the international standard. Dickson was a poor choice when the former president appointed him, and he hasn’t grown into the job. A balanced hearing would show this.
The proper role of FAA in this and any similar controversy is to conduct its own measurements and share them with the responsible parties. It should share its findings on altimeter vulnerabilities and leave the modeling in 5G emissions to the experts.