Sealing that long border especially when people look so much alike is not possible. Equally importantly, we (India, US, UK ....) are quite interested in ensuring Pakistan achieves peace, law & order and social stability, since that is the only way to stop terrorism in the long run.
That is not an excuse, Germany had their "wall" dividing ONE country into two, are you saying they didn't look like one? Are you saying Pakistani/Indian borders are open for everyone to walk in and out? or does it mean Indian and Pakistani are miles apart in looks? It just needs will of the governments to make it happen, spending billions of dollars on a war is okay but spending a few millions is not?
don't understand your parsing the 'we'...pls elaborate?
As you said earlier, both Indians and Pakistani shouldn't poke nose in others' matters so please stay away from this. Most of it is our internal matter and we would be able to solve it if foreign hands can keep their fingers away.