With respect to moral equivalency and becomming just like your enemy, it's important to remember context. The Cylons started the war. The Cylons tried to exterminate all humans. The Cylons have been not simply murderous but cruel. They made it into an exterminate or be exterminated issue.
Humans have the ability to be murderous and cruel. We also have the choice to not be murderous and cruel. Cylons also seem to have the ability to make that choice, it is not a choice that has presented to them to make.
Sharon didn't just violate her code once. She did it a number of times.