If they'd of declared sooner, they'd of gained extensively. Now it's just too late. People drastically underestimate the benefit of top feeding, especially when their core was just below the same range as our core. Since they started retalling, we've had to stall our razes and focus on removing any threat of war. To our benefit, they waited so long to declare that we were able to cut their top offenses down by ~200k+. Without outside help, they have no ability to win. They only have the ability to damage our core and prolong the inevitable. Since there are other kingdoms now razing them, this is a lose/lose situation for them. The real lose/lose part is that they admittedly have no intention of learning anything from this. So in the end, I imagine this will just keep happening.
We cannot stop outside kingdoms from intervening (they already have begun raze killing into the war). As for behaving in a worse manner, that's in the eye of the beholder. Robbing into EoWCF is seen by many as disrespecting war. In their eyes (the eyes of those doing the razes), it's as DHaran said.