The main consistent principle on the social-justice-left is rooting for the underdog. By that logic, a Hindu minority in Pakistan saying "destroy Islam" is good, but a Hindu majority in India saying the same thing is bad.

Of course the side effect of that belief is that people spend a lot of time trying to prove they're underdogs, e.g. look at kids on Tumblr listing all the ways they're oppressed because they have self diagnosed ADHD/aspergers, or trying really hard to claim ancestry of an oppressed group.