I've only tried on the pirate mining station in Galatia but why would ordering a saturation bombardment of a station be a warcrime so bad every faction becomes hostile? Its just a station. Maybe if it was specified to have some massive population of like tens of millions or something but a station with three thousand people is no big deal i would think.
Well, even with a pirate station you'd still kill a ton of civilians with a saturation bombardment. It would be like having an army surround a town infested with terrorist forces, and turn it into a heap of rubble with heavy artillery fire. Sure, you killed the pirates/terrorists, but several thousand innocent bystanders still got murdered in the process.
What kind of planet it is likely doesn't play much of a role, since I assume even a Saturation Bombardment is more like the WW2 Air Raids on Germany and Great Britain, which wouldn't impact the local Environment
too much since you're "just" bombing the cities, infrastructure and industry, rather than doing anything approaching Warhammer 40k's Exterminatus, or Star Wars' Base Delta Zero. And stations are rather easy to build, maintain and replace, considering how many the Pirates or Luddites can pull out of nowhere, which is why it wouldn't bother anyone from a material standpoint if a few get blown up (and likely won't even look up from their newspaper if it was a purely military installation like Pather Stations).
Now, if there was the option to completely wipe out a planet's biosphere and render it uninhabitable (without alot of resource expense anyways), THAT would likely *** off everyone, since Terran worlds are hard to come by.
Or for short:
Everyone hates you because you just murdered a few thousand civilians, BUT what kind of planet or station you do it to isn't important because the damage is rather small compared to the planet as a whole, or nobody cares because it'd just an easily-replaced station.