Ghauri, Ghaznavi and Durrani were first-class pillagers. they were forced to repeatedly attempt invasions toward the plains because their barren Afghan desert could not grow crops worth mentioning to feed their populations. and people praising them, hats off to you. you may have no affection for this land but for me the fertile soils of Punjab and Sindh are flesh and blood.
every time they used to burn down dipalpur or lahore, our ancestors sung praises to high heavens because they happened to be musalmans right? you think they came to spread Islam? they were driven solely by greed and the very real dilemma of feeding poor Afghans. all they did was invade, burn or murder whole villages, rape, loot and tax, then go back. because they knew this land was not theirs, as vindicated by how shortlived their occupation was.
In fact, the kind of sins, immorality they personally committed and allowed their underlings to carry out, makes them muslim only in name. they were far from pious in their acts. Quran and Sunnah teach to only love and spread tawheed in the most peaceful manner possible. where killing any human, muslim or non-muslim, is equivalent to killing all of mankind.
all three of them, not to mention countless others, would have faced tough questions on Judgement day, because Afghanistan wasn't invaded, ransacked or even posed a threat to by the people that they slaughtered. so they can't claim higher moral ground or religious justification. for them massacring innocent, defenseless natives was an enjoyable hobby, pastime and entertainment. but what goes around comes around. afghanistan remains what it has always been.
The first people to come populate coastlines from Karachi to Kolkatta were Africans. Not too different from modern day aboriginies in Australia.
finally someone on this forum with a sense of anthropological history related to early humans. the only slight correction I'd like to make is, the second wave of migrations from east africa actually arrived by water somewhere at the south-western coast of subcontinent, near present day Kerala or thereabouts, according to genetic markers.
many of those proto dravidians started moving to northern plains of the subcontinent around 40-60 thousand y.b.p., where their genetic characteristics naturally diverged over tens of thousands of years from their kin that remained in the south. academic discourse widely agrees that the Indus/Ghaggar Hakra civilization was populated by people already native to the land thousands of years prior, i.e. 'Ancestral North Indian' descendants of those proto-dravidian migrants. once it declined most likely due to natural calamity, the inhabitants did not go underground or vanish, but migrated eastward closer to himalayas and yamuna-ganga to form the backbone of Ved civ.
Central Asian populations had zilch to do with Indus valley, and it's very questionable whether they had anything to do with the Vedic civilization (a British colonial narrative). again, genetic markers only indicate a central asian addition to the consistent subcontinental gene pool within the past 2,000 years. no such evidence, whether in the Vedas themselves or the markers, exists to postulate their assimilation or substantial settlement here before that.
The reason some haplogroups are shared between with Iranic and C. Asian populations, is because those people trace their lineage to the first wave of migration out of East Africa through egypt and arabia/levant, and the entire spectrum of genes (incl. y- and mtDNA) all over the world were present in that initial east african population (where the orgins of modern homo sapiens more than 110,000 y.b.p lay). hence, we are their distant cousins, just as we're related to chinese and native americans in a far off way. but owing to natural geographic barriers or prosperity of their own agricultural civilizations, Iranic peoples & central asians did not migrate to leave a genetic presence in South Asia until the past two thousand years. When they did, it was as a peripheral, distinguishable group that adopted the local culture, not as people who 'introduced' it or formed the core of its early articulation.
genetics and darwinian insights are a wonderous thing, truly. few fields stimulate thought and awe as much. now I know why pioneers in this field, wherever they were from, had a distinctly humanist, egalitarian disposition regarding how society should be organized. In fact the same is true for all great minds that pushed limits of our knowledge about the universe. refer to Albert Einstein's 1949 essay,
"Why Socialism?"