He hate people based on his perception...specially those who have no strong sense of self. In his mind, anyone who cant remain true to his or words..are big crime.
Unfortunately these traits he found in three people on constant basis...those people happen to have one common link of faith. Additionally, Karishma is self confessed selfish.
Thats why Punz hates Ali...who is self confessed double dholki. Nigar initially talked sweetly with Punz in jail. Then she chose BG...I think he had very short time to judge her. Arya was a bachha, n unintentionally funny...even he didnt know what to say or behave. so by default he become double dholki.
Even today during nomination, he was upset at Praneet becoz in his books, he played a double dholki game.
Hope it clear your doubts about Punz's biasness towards certain people.