That article seemed off to me seeing as the points coming from the group sound identical to MRAs in the USA and Britain. If they had genuine male repression I'd have assumed they would have more serious issues, like, say suffrage or the right to sit in their political institutions.
So I went to google.
Turns out that the culture is matrilineal, in that children take their mother's surname and the youngest daughter inherits the majority of the property (on the assumption that she will be the parents caregiver), but traditionally women have been excluded from politics.
Looking at the legislative assembly for the region (Meghalaya),
there only seem to be 1 woman out of 60 seats. All positions listed as office bearers (eg, those with formal power) on wikipedia
are men. It's also worth noting that there is a committee especially for women's liberation and empowerment, something you wouldn't expect to see if women were already supreme in the area.
As for the more traditional, tribal structures,
wiki has some information, with some more on the page of
dominant groups page. Not much of that is sourced, but a quick search turned up more sources that
seem to make the same points (there is a lot more in that book if you care to read). In brief, even the traditional political structure was male dominated. It actually went far further than the modern, formal system to actually formally exclude women from the process entirely.
It's worth noting that wiki has the sex ratio as 986 females to every 1000 males. That's compared to 940 for India as a whole. Make of that what you will.
And going back to a
2003 BBC story (linked at the bottom of the original), the call for greater men's rights was noted alongside a notable increase in rape and sexual abuse of women, as well as general domestic violence. There is a strong undercurrent of tribalism just to make things more complicated.