Some people that gank are practising the parameters of a build to see how it handles, how it flies, how it can be improved, how they can improve their use of it so they're taking any opportunity to use that ship. People experimenting are usually good or improving.
Some people that gank are waiting for fights, or engaged in activity to trigger fights, so ganking in PvP systems is a way to find them and pass the time. People practising are usually good or improving.
Some people that get labelled gankers are looking for PvP so they're pulling any combat ready ship and seeing if they shoot back. People seeking out symmetric PvP are usually good and improving.
Some people that get labelled gankers are engaged in BGS or power play activity which someone is having an effect on but not paying attention to how they're gameplay interacts with others so they get shot at but have no idea why. People coming from those activities are generally in heavy PvE fitted ships dipping their toes in PvP and will get quick kills on people that fly like an NPC but have trouble against someone that knows what they're doing in PvP, including people actually ganking.
Some people that gank just want quick kills because they can and could have any level of combat skill if they're in a ship fitted for it and know how to select targets.
Ganking in itself is an activity with different needs compared to symmetrical PvP with ships designed to chuck out maximum DPS whilst being capable of surviving, but not necessarily winning, if pulled by somebody fitted for PvP. If a ganker runs when pulled, don't assume it's because they're not skilled enough for symmetric PvP.
