I'll say it now Sheb: Yes, that was a dick move on our part. I make no excuses to the contrary. I do however give you the following:
Look at your income, colonies, econ rank last turn and your expenses into Colonization (which i didnt think you would get that high in 1 shot, grats). It would be current turn when you'd trade (if you would) and NEXT turn before we got it, and the turn AFTER before our use of which would prove useful or not.
Now in the next 3 turns (this, next, and next+1 to colonize our crap areas) you'd have gained how much income? Dumped how much into Econ/Manufacturing? Explain how, in any way, we'd be able to defend ourselves (not counting an outright attack against you) when you have the production power and income of 2-3x our combined output.
While true, recruitment would need to be known to us upfront. Which would basically give us 1 turn to try and gut as much of your production as possible. Unlikely to happen since you'd have had a buffer of disposable terits to meatshield behind while production completed. True we'd have had enough warning to produce our own, but your income, size and manufacturing alone would have made it a losing fight for us.
We were stuck with 2 terrible situations, one potentially worse than the other. So we chose the only one that ASSURED our survival. It also evened the playing field. Even if i were to cede back the lands of yours i have, the expenses you burned on colonization and losses to income this turn evened us out temporarily.
Side Note: That research i did came out better than i thought it would.