That line is from Razor, which fans generally agree screwed the character beyond recognition anyway. I am judging the character by her Season 2 appearance.
In other words you're picking and choosing in order to prove you point.
At the end of the day, Cain got herself shot dead, Adama got to see a new world, a new home for mankind.
Also if you go back and watch the mini-series Adama was pretty much on the verge of doing very much what Cain did - take what they needed and leave the survivors to fend for themselves.
The RTF showed more sense than Cain did. They didn't hang around seeking revenge - they got the hell out Dodge and looked for a new life.
All Cain's actions would have succeeded in doing is getting the Pegasus destroyed having done no real damage to the Cylons. Sure she might have had a few victories by they would have been Pyrrhic to the end.
Guerrilla tactics are well and good when you're fighting an occupying force whether it's 1940s France or New Caprica. Going Guerrilla against them after they've destroyed 99% of your society achieves nothing.
I guess Cain can be summed up the adage - when you set out for revenge, dig two graves.