There isn’t an obvious “why” David Draiman, frontman of Disturbed, would say this. But one reason, and this is of course just speculation, would be this:
Causing things like cancelled gigs and mass booing at shows. While that’s just my own speculation, who could have guessed that signing bombs used to murder children in refugee camps would cause such a backlash! Sarcasm aside, it’s going to be a welcome sight to not see Disturbed for a while.