Well first of, Stardock is the publisher not the developer. That's Ironclad. Second, mods have never truly been supported by devs. Many current developers allow mods to happen and even provide tools but any mods that break the game (aka going over RAM) are not the developer's problem. Hence no support.
I'm pretty sure no game has ever given technical support for mods.
What most people mean by mod support in a game is that there is the ability to mod the files and some system in place to support using them. Sins definitely qualifies.
But to answer the main question, the devs have said they looked into LAA, but some PCs do not handle it well. For some fraction of Sins players, using LAA actually REDUCES stability. Hence the devs don't make the game.exe LAA by default. Those that use mods and have need of it are free to try it, but enabling it for everyone would just make stability worse. And then it WOULD be the devs problem.