In Lebanon it would have tipped the delicate balance between Christians and Muslims (not that that happened anyway)
Although it happend anyway o/c. And probably wouldn't have been so bad if they'd tried to integrate the refugees into society; besides it would have provided a lot of employment in construction and might have helped to stabilise the economy.
Which is the reason why they didn't do it, but it's still a terrible thing to do (or not to do). And again, if integration had happend there would be less tension between the refugees (aren't they in a majority now?) and the Government.
Well yes, refugees do change things. A lot in some cases. Same with immigration in general. But it's still no excuse to not integrate refugees.