You can get enough morality to pk a couple of people by just remembering to donate all of your extra potions stones, etc from farming. Just toss them in the alter every time you're in town and your immo will be high enough that you can get away without even wrath for the occasional pk of some newb muscling in on your farm spot or leeching your dp.
Immo Cleansers were majorly abused by PKers camping spots like the Gray Bridge and other popular places, not letting anyone play the game freely. Then with a single Immo Cleanser they were back to 0 Immo (No matter how many slaughters or PK's they had) and could continue to pk endlessly.
Even if you accept one of these "justifications" the truth is most PKing is done purely for PKing's sake. And it is nothing more than bullying: The impairing of someone else's day just for the petty power fix. Habitual PKers dont need better immorality soap or a more efficient Alter system. They need help in the real world to address their blatant self-esteem issues. The lonely, the failures-in-reality, the unloved, PKers also need our pity.