Capsuleers live in a world with endless hordes of raving lunatic zombie killers. NPCs tend to open fire without asking questions, rarely if ever warp out, even if they are obviously losing. NPCs appear to have no regard for their own lives.
NPC acting like hordes of zombies is a major dehumanizing factor for capsuleers. The opponents are effectively mindless, robotic and in endless supply.
I've always found the suicidal zombie NPC "never retreat, never surrender, even in the face of inevitable and pointless death" world aspect wholly unbelievable. This is better explained by the technical limitations of having to fly Captain Kirk style than by some kind of policy of death before retreat maintained by everybody from the Guristas to the Minmatar Navy (whose specialty is supposed to be hit and run, isn't it?).
I imagine something like this:
"Captain, it's confirmed: no conventional craft can maintain that rate of fire. The attacker is a capsuleer!"
"Damn! ... Alright. Order the retreat."
"Understood, sir!... Um. Sir? Engineering reports that due to the suddenness of the attack, our FTL drive is still offline. Warp drive spool-up should be complete in 48 minutes."
"... Double damn. Also, fuck. Well, let's keep at it. Better get the escape pods prepped."
"Yes, sir."
In other words, the only people who succeed in running away are those whose ships are actually able to do so (scripted, or the occasional patrol of belt rats that manages to warp out).
As for their "shoot on sight" aggression, consider that, to a rat, (1) if it's not obvious that the ship is a capsuleer vessel, it looks like either easy prey (profitable) or a lone scout (extremely dangerous to let escape); (2) if it IS obvious that the ship is a capsuleer vessel, it's the craft of an infamously murderous demigod who probably has zero sense of mercy or compassion-- which you're stuck in deadspace with at least until you can manually fire up the old warp drive. In that case, time spent broadcasting a surrender or trying to flee is lost time that could be more productively spent fighting for your tiny life.
It's not a perfect explanation by any means, but it's the only one that makes a lick of sense to me.