Most areas of the port are private lots and aren't accessible to the faction, not to mention that it would be simply impossible to permanently monitor all blind-spots.
It benefits the San Andreas Port Authority and security companies that are contracted by private lots, it benefits illegal role-players, I fail to see your point that it doesn't help anyone's RP experience? It's not a matter of hurting truckers, as long as they can't get jumped where they're loading their vehicles they should rarely get mugged.
Your attitude is totally toxic though bud, 'bad ass security character', what? Grow up.