This is an incorrect pramANa. A simple glancing of svAmin sAyaNa’s bhASya and the context of the Rk would explain it. The draSTa is the child RSi - shishu A~Ngirasa as can be seen from the informal way he calls his parents tata and nanA. https://t.co/nM4lA80fRc 

The sUkta occurs in the book of the somapavamAna. So the hymn is of course seen in that context. Here the child sees his father as the Rtvij and the mother pounding the flour to make the puroDAsha.
Why go for unnecessarily wild fantasies?

I have seen this example even in my school history book. Probably makes for good propaganda, but seeds weird ideas.