HS bump/gank has definitely caused some players to leave, but on the other hand it has also caused some players to stay.
I think overwhelmingly those players that left due to HS bump/gank, did so cause they overstuffed their hull and, worse, became complacent/careless (either due to ignorance, laziness or greed).
So in other words, they left as a result of their own mistakes, not because of the actions of others. Before anyone calls this “victim-blaming”, it isnt. Its just recognizing that someone that loses substantial assets due to their own mistakes is understandably going to be upset and often try to assign blame to anything/anyone except themselves.
Even after that, which is futile, and they have vented their rage, they are left with the hard fact that they have lost significant assets they have played for, and have to start regrinding them.
Such is the reality of games with permanent loss, such as EVE, and which many players are unused to due to the lack of such games on the market and in their personal previous gaming experience.
They approach “loss” with the wrong mindset, as of yet.
They havent (famously) “HTFU”.
Its all fun and games, till the rude awakening of what EVE is.
In any case, Id think this is only a very small cohort in EVE, and barely makes a dent in the overall player attrition in EVE.
CODE makes a lot of noise about their activities, cos they are CODE and thats how they roll, but their actual impact is very small in the grand scheme of things.