When I hear prayers given by brothers why do they only pray for other JWs not all people??
To pray or not to pray is a personal choice. And people also have a choice as to whom they want to include in their prayers.
If your friend meets with an accident, you may ardently pray for his recovery. However, this does not mean that you are indifferent and callous since you did not include all other people who must have met with an accident that day.
There were instances where even Jesus was specific in his prayers. John 17:9: I pray for them: I pray not for the world, but for them which thou hast given me; for they are thine.
I appreciate that you pray for everyone. However, when we start judging whether others are doing the same in their prayers, we are assuming God's role. Prayers are made to God and let God decide whether whose prayer is appropriate.