Though Matt explained the context of that comment, I will deviate from the general tenor and say that this part sounded objectionable without that conext.

I am not a religious person, and can't do much with the concept of prayer, but I do tend to hold the standard of coherence against the religious. In this case, as far as I understand the New Testament, Christians would be obliged to have compassion for everyone, including sinners. So had this "I'm just not praying for him" been just an off-hand comment, or even if it isn't but the poster is religious, s/he would be/is a hypocrite in my eyes.

_{*Lunatic*, n.
One whose delusions are out of fashion.}