Yea, basically several times a second they check every single allied ship in the system to see if they can assist it. 20*7000=notSoBad. 1500*53000=unfriendly.
It's the sort of thing we *could* throttle like autotargeting, or use a more rollup-based approach to finding assistable ships, but in non-cheat cases it would seem unnecessary.
Edit: btw, with the engies off and tabbed out to the galaxy map I get about 80ms/cycle, which is about half the target framerate.