Not sure how? Half of BD supports Pakistan in cricket and the other half India, when a match takes places between them. My whole family and extended families all support Pakistan whether it's against India or any other country. (I don't watch any sports or care about them, so don't have any preference).
For my personal perspective, just like the current day Japan and Germany shouldn't be judged based on hitler era, so shouldn't be Pakistan. Unlike Japan and Germany, median age of BD and PK are in their early or mid 20's. Meaning most of the people weren't even alive 47 (?) years ago when the war took place. To have any sort of grudge against those people because of the war is plain ridiculous.
I do judge on their present behaviour though, and I don't find them threatening in any way since we don't share any border and no chances of clash. Pakistanis also doesn't have any interest in being a threat anyway. I am for increasing trade and diplomatic relationship with them precisely because of that. Since none of us are even a remote threat to each other for the very long foreseeable future.