Fighting is means to a goal. Not the goal itself. Dirty sometimes enhances efficiency but what's the point of going all dirty on someone and break them when you can achieve a goal of either escaping from danger or end it quickly instead of more torture. If someone is bloodthirsty on producing a snuff of dirtiest fight on another human I'd say that person's really sadistic without any other goals than enjoy sadism pleasure from a human being getting hurt.

You fight to get to your goal. You don't get entangled and prolong the fight due to emotional problems just to intimidate the guy.

Define dirty fighting.

There are no rules in the street, no referee to break up the fight, no bell to ring for the fight to start. Its just you and your attacker(s)

First off if your life is in danger it isn't dirty fighting, but technically yes it can real bloody/dirty real fast

No its one of the oldest sports? a part of culture .. and its natural to get in fights in the younger ages