That's really interesting. I had just the opposite experience, when I moved them to a rack system they all mellowed out. What kind of rack is it? Are the tubs solid or clear? I have an ARS rack with solid grey tubs, I've seen people have success with the clear tubs but I would think that would stress out the snakes. Is your rack system stable, does it move around at all? The rack I have weighs several hundred pounds and is as solid as a brick. Maybe a wobbly rack system would do that? Does it have any weird smells? I don't use any hides at all, but I do know that when my snakes are under a hide and I take it off of them real quick sometimes they freak out and get very aggressive.
I would try taking out all of the hides (as long as you don't have clear tubs). I usually slide open my tubs and if I see my snakes all balled up with their head buried I don't mess with them. If they pop their head out and look like they want to explore I take them out. Now I don't use any hides at all, I just use the built in water dish system with Dixie cups, nothing else. I even have very small hatchlings in big 70 series tubs, they just ball up in the back and are perfectly happy and have been eating twice a week. Sorry to hear about your aggression, there's nothing worse than an unhappy snake.