You must remember that Alice Linsley was writing from the viewpoint of Theological Anthropology, which Wikipedia describes under the label of Christian anthropology, a sub-field of Theology, not of the social science of Anthropology. Under that viewpoint, yes, the “Table of Nations” is a real thing, they did all really speak the same language before Babel, Noah and Nimrod were real people, etc, etc.
However, within that viewpoint, the Bible really did mean “Egypt”, “Pharaoh”, the “Sinai”, the “Nile”, etc when it wrote, in Hebrew, “Mizraim”, etc.
Of course if you venture beyond this viewpoint, things may look very different, as @John_Harshman said:
Looking outside this viewpoint, we find opinions that the Harappans spoke Dravidian, a non-Afro-Asiatic, and in fact non-Indo-European, language unrelated to Hebrew and other Semitic languages.
You also find that you have to find non-Biblical evidence to support Bibilical claims about the existence of volcanoes, orders-about-straw-in-bricks, etc, etc in the Exodus narrative – because stepping outside this viewpoint puts all purely-Biblical claims into question.
So neither accepting the Theological Anthropology viewpoint, nor rejecting it, helps the Israelites-from-Indus argument. To support that argument you need to pick and choose claims from within that viewpoint and from rejecting that viewpoint – which leaves you with a Special Pleading fallacy – as your claims are neither fully consistent with accepting that viewpoint nor with rejecting it.