Because I am crazy and want to run Reznik1 with all the wracks possible.
I have many jacks and some other models that have wracks attached to them in various ways and the idea of starting with 6 of them on the table and adding more when Reznik gets into melee just seems silly and fun. And trying to chain blast a bunch of Wracks seems like too much fun too.
A maximum of 3 wracks, free or otherwise. Since CM starts you with upkeeps in play, you dont need to pull on turn 1, so turns 2,3, and 4 are turns to pull and yoy lose an average of 1 wrack in those turns, so youll have a wrack for turns 5 and 6 at the very least.