It's a matter of radar resolution. Radars can't distinguish flies apart from each other, so obviously there are technology limitations anyway.
However thats not the case nowadays. Even if you had a nasty radar from the 80's you see that the trace is twice the size it should be. (We'll I'd hope)
I'd assume that military radar ops would be looking for this, as this is a great way to sneak assets about.
When they say they put national security second to investigating the flight, what they're saying is that they're now exposing a lot of information about these radar systems with other countries in order to figure out what happened.