This poster assumes patriarchy arrived on the Indian horizon along with Aryans. I am not so sure. At Quetzalcoatl discussion forum : Tribes/nomads least bothered about purity of women. But sedentary population overly. Indus valley was sedentary. It must be patriarchal.
South Indian matriliny:
One thoery : The tribes that took up agriculture late remained matrilineal. Agriculture arrived in Kerala around 7th century much later than any other parts of India. Another example, a Tamil community called Pallar that left their tribal life to mainstream agrarian life remained matrilineal for much part of the history.
You find matrilineal communities among Tuluvas, Malayalees. But very few Kannada and Tamil communities. And not yet a recorded Telugu community. Some believe Andhra is the urheimat of Dravidian speakers. It could also be the first South Indian region to become agrarian society(because of Austro-Asiatic Haplogroup R2 rice farmers from the East) which spread to Tamil Nadu and Karnataka regions and last reaching Tulu Nadu and Kerala. The geographical locations of these regions of course support this view.
Why were Aryans not culprits?
First, they were nomadic. Second, the present genetic studies show their numbers might be very small. Were they from Eastern Europe then where are Haplogroup I and N lineages? Were they from Western Europe then where are Haplogroup R1b lineages? Were they from Western Asia then where is Haplogroup E3b lineage? Haplogroup R1b is present. But only among non-Brahmin castes. Third, I do not believe Hinduism is just a blend of Vedic and native beliefs. In my opinion, it also has a very strong Semitic character.
PS: Anyway, I am not really sure what that blogger wanted to say. The way she mixes the things is very interesting. While Aditi was definitely a Vedic figure; the unclean menstrual blood concept in South Indian society was(the untouchables were called H(P)oleya where h(p)ole in old Kannada meant menstrual blood) used as an indication of native origin of purity-pollution concepts, the basis of caste concepts.