The DoD already had something like Starlink. SpaceX is trying to sell a lower cost version of the same thing, but cost savings isn’t that compelling for congress who sees costs as much as a feature as a bug.
The NDSA doesn't actually exist yet, and SpaceX is presently the only company that could launch the larger versions of it.
Starlink has more total bandwidth and lower orbits, but the US military only needs so much bandwidth.
Anyway, it’s vastly easier to destroy LEO satellites than Geostationary ones. A surprisingly tiny missile fired from an aircraft doing Mach 2 can take out Starlink satellites as you only need vertical speed the satellite provides energy at collision, but geostationary orbit takes significantly more. https://en.wikipedia.org/wiki/Anti-satellite_weapon
Yeah, and they want a hell of a lot more. Seriously, read up on NDSA. For the transport layer they want hundreds to thousands of satellites in LEO.
What they want from NDSA is multiple different systems each with a separate focus that can all use a uniform transmission layer.
Starlink has the very nice feature of being robust, just by virtue of having soo many satelites. China can easily knock out 4 geostationary satellites. But hundreds of low-orbit satellites make for a very difficult target.
I wouldn’t be surprised if a single HARP style light gas gun couldn’t cheaply take down every Starlink satellite for a few hundred million total. The best defense is having a wide range of satellite orbits and the ability to quickly deploy more. If nothing else, a single nuclear EMP could wreck a huge swath of the Starlink network.