The Backstreet Boys love their fans in Israel, but they love their families more -- which is why they regretfully cancelled a bunch of concerts there, according to A.J. McLean ... who's standing firm on NOT choosing a side in the conflict.
We saw McLean in Malibu Tuesday and he explained that if the cease fires had held, BSB might have gone through with what would've been their first shows ever in Israel this week.
A.J. reveals when they're planning to reschedule, and adds he's praying for both sides, because ... "You can't pick a side."