Ignoring the somewhat ad hominem nature of the argument, you do
realize that "Indic" is something that is used at the Unicode
Consortium to denote the group of Indo-European languages comprising
Sanskrit and the modern Indian languages that are its descendants.
And?
I don't recall using any argument that suggests Indic can not mean a group of Indo-European languages, just that it differs with context. In fact, usage by the a specialized body, and not a general one, lends credence to the argument that its usage is differential based on context.
And Last, Unicode Consortium is what you should be taking the lead from, when it comes to word usage - Not a dictionary, its etymology, or cultural usage within a continent, because a non-profit based in US registered in the 90s, would be the appropriate authority to define what the correct usage of a word would be.
-Theo