The imaginary "proto indo-european" language is a very deep seated racist brother of the Aryan invasion theory. You can read the wikipedia article and the start of this mythical language construct with Sir William Jones who wanted to make his study of Sanskrit fit within his Christian worldview. He found the Sanskrit, Latin and Greek related and decided that there is some mythical imaginary language that preceded them. How could well educated Britishers and Europeans come to the conclusion that Sanskrit was indeed the ancestor of Greek and Latin.
You seem to agree with the linguistic consensus that Sanskrit, Latin and Greek are all related. You seem to depart from the consensus with the conclusion that because they are all related, they must share an ancestor.
If that's so, how do you account for the relation between Sanskrit, Latin and Greek (and Russian, and English...)?
Or do you deny the relation altogether? Do you have a competing theory that you could point me to?
How come that "the theory that made up an imaginary language" correctly predicted the existence of laryngeal phonemes in the Hittite language before the Hittite language was even known to exist? Stroke of luck, that a group of unknown consonants from an "imaginary language" appeared in a real language in exactly the right place in the right words?
Also, the notion that the PIE reconstructions describe a "language" in the sense that we usually understand it (a vernacular tongue of a group of people in a single time and place) is a false one: even though the reconstructions with very high likelihood represent individual IE language features in an old form thereof, it would be a folly to try to slap them together and say "this is a language that someone spoke", for the same reason you can't reconstruct individual genes from the tree of mammals, slap them together and say "this was the first mammal". It doesn't work like that. What you get is a constrained probability function over possible languages, not a single solution with 100% probability.
It's not racist in the least. If Sanskrit is the ancestor of Latin and Greek, then there should be Sanskrit a superstratum in Latin and Greek. However, there isn't. But there are common elements in all three languages that could only have come from an ancestor language.
What you're doing is ad homimen: discounting the theory based on personal attributes of the person who came up with it.
Can the theory stand on its own regardless of the personal motivations of the person who came up with it? Then the theory is solid.
