Yeah, that was a major surprise when I discovered that the AI races in this mod would try to RAM with their colony ships. But once you know it's going to happen, it simplifies the problem of chasing down colony ships...
The Sergetti are now at war with every other race in the game, even the neutrals. They've suffered some losses but not very much yet. They are gonna be in very deep trouble in a few more turns when my shiny new light cruisers go charging into the adjacent lightly defended system, and that will put me right next to their home system. I am thinking about a 'strategic' strike directly into the home system and then going back for the small planets in the intervening system. If it works, it'd be a major gain for me and a major loss for them.