Seems to be broken on Gleba stompers, be aware.

Thank you for reporting this, TwinDragonsOfChaos.

I currently have no way of testing this on those enemies, yet. Do they stay hostile?

Yes, they are hostile

I see. I'm afraid there's not much I can do about it currently, as I don't own the expansion...

Setting peaceful mode seems to work, however the button does not update when switching surfaces. Set peaceful mode on nauvis and switch to gleba, the button shows peaceful but the gleba enemy are still hostile.

I've updated the mod for 2.1, and rewritten it so the button is now moved to the shortcut bar.
The mod is now fully compatible with Space Age, and works on Gleba and Vulcanus as well.