50/50 chance is not small. That is a very real chance we'll get hit by a powerful enemy that's a genuine threat to us and we should prepare for it accordingly. 50/50 is not a low enough chance that we should discard the possibility of invasion for the sake of better defence against an enemy we'll do fine against no matter what.
God damn it. We should've done this thing earlier instead of that gravity fundamental action. What a waste that action turned out to be. Anyway, you're wrong about one thing. The task force only takes up to a few years to get here, so even with no large Abomination force in the region, we could still get hit by an Abomination enemy from beyond the region.
@Chlof, Gravitic Array Program would greatly boost our system's defences. If we get hit by an Abomination space fleet, it would greatly improve our victory odds.