Aiki teaches aiki. The only thing that teaches fighting is to get in a fight. (Voluntary or not
) People that get in lots of fights get better at fighting, there is a huge amount of psychology and 'role-playing' involved in real fighting.
I practice aikido so that I don't have to/want to/need to fight.
If someone asks me I say 'Aikido is an art of peace' (Honest)
Also, I get asked this all the time