1) Was it ever proven that Cain's sanction of torture 'netted any actionable intelligence? For that matter, once any useful info had been gleamed, why continue the rape and torture, beyond petty desire to hurt Gina.
2) By arguing that it was "guerrilla war tactics" then that argument basically says "it's okay to rape and torture" the "good guys" so long as the other guy is using "guerrilla war tactics"
Cain was a sick person and a poor Commander. It isn't even about traveling to Earth. Once she realized that the Cylons had other interests (re: Galactica) she should have rounded up as many civvie and military survivors as she could and headed off the chart for a planet they could colonize.