I know it's configurable and there are some good arguments either way, but impalers ignoring any kind of static is weird to me. That's what they are for, kill static.
You can manually target a closed razor if you need to, but why make it default to ingore? If anything, a target buildings only toggle would make more sense.
The only case I can think of to not target an armored static is if you try to kill a disabled razor/deso/gauss that is getting repaired faster than the impaler(s) can destroy it. Sure, I guess... but then that's not really a failure of the automated behavior of the unit. Rather, it's a failure of the player I would suggest. Bad targets avoidance aside, attack move impalers are also prone to target units in motion/wobbled radar dots and miss perpetually. I don't think anyone thinks that's a problem that needs fixing, but is rather an argument for the player to take manual control of certain units in specific circumstances.
I'm pretty sure I've seen other static behave strangely. Like desos ignoring dirtbags maybe? Or maybe a spired deso ignoring certain low cost targets because the heat guns are no longer in range of ground units and the main cannon does not target low cost units?
I will admit that most of the changes I made came down to persomal preference. For instance, even if I could want some units to ignore solars, I never want to. I would rather have any unit that is in range of a closed solar to shoot at it than to keep it's weapon ready. Odds are that if a skirm gets close enough to a solar to shoot at it, there isn't anything left alive to defend that solar.
Moderators also ignore drones I think, which they can kill. A ball of moderators will just let itself be picked apart slowly rahter than shoot back at free unit.