I'd argue that if they put up a Palestinian flag, it's clear that Palestine is being referred to.
In principle, though, I agree with your first point
Sure, they're referring to Palestine in this case. But, it doesn't necessarily mean that they're fully "pro-Palestine". They're undoubtedly pro Palestinian kids. But, that doesn't mean that they side with Palestine over Israel in the general case.
Well they should... If You or they know the history of Israel
I'd argue that if they put up a Palestinian flag, it's clear that Palestine is being referred to.
In principle, though, I agree with your first point
Sure, they're referring to Palestine in this case. But, it doesn't necessarily mean that they're fully "pro-Palestine". They're undoubtedly pro Palestinian kids. But, that doesn't mean that they side with Palestine over Israel in the general case.
Well they should... If You or they know the history of Israel