They are hypocrites, but I've noticed that in reality as well, most of us are. I notice many families, who although claim to treat the daughter-in-law like a daughter, and to some extent even do... but there is always that little back-biting that the saas does behind the bahu's back, which differentiates DIL from daughter. It's true, sometimes they show preference for one bahu over the other if they don't have daughters. Two sets of rules for beti and bahu. How many families have we heard beti comes and squats at maike but the bahu wanting to visit maike is criminal in their minds. SDS portrays the double standards of a saas to a tee. The ones that claim they treat their bahus like betis are usually the ones who stick it to the bahus.
Thakurs are a classical example. They should realize now that it's not so pleasant when you yourself are on the receiving end.