how come in 1947 , our Indian muslim brothers who escaped india had decided to all go live in sindh. was that accidental or was it easy to transport to. other Pakistanis provinces didn’t get this influx hardly any I always wondered on this.
There is no way of answering this without being controversial or sounding bitter.
This is because Punjab did not accept them. They did not let non-Punjabis disembark the trains. A famous story is that they told the train filled with migrants that "Pakistan aggay hay (Pakistan is further away)." There was nothing for them in Baluchistan & the NWFP wouldn't have let them in either.
In the end Sindh and Bengal decided to take them in, at least till things settled down. Even though, Quaid promised immigrant population would subsequently be distributed to all provinces equally that did not happen. IMO, major culprits in ensuring that the immigrant population was not reallocated to other provinces were Liaquat Ali Khan and other migrant cabinet ministers. Sensing they did not have any constituency within Pakistan where they would ever achieve winning number of votes they not only ensured the settlement of Urdu speaking people in Urban Sindh - particularly Karachi where the capital and cabinet members were based - but also systematically forced the Hindu Sindhis out. This went on till the 1950s. What does not come up is that there were series of pogroms against Sindhi Hindus immediately after partition. During the first one Quaid successfully intervened to save lives and properties of Hindus in Urban Sindh. But the one in the 1950s, the Hindus were left helpless. I once had a discussion with a Hindu Sindhi whose family migrated to India. According to him, "the Muslim Sindhis did not so much laid a finger on us. So, you can guess who did."
While Nehru in India was quick to draft the country's constitution within couple of years Liaquat did not so much drop an ink on a paper to draft a constitution. Doing so would have meant election and election would have meant Liaquat's removal from the premiership.
Sindh Assembly members like Syed Miran Muhammad Shah in the end went along with settling Indian immigrants in Sindh. Much of Karachi's legal extensions you see today were planned by that man to accommodate the unnaturally increasing population. Of course, Sindhis (and Bengalis) were quick to realise they were in the wrong. Didn't even get a thank you note.
All of the above that I have said does not, however, provide excuse for what happened in BTK today.