First of all, it undermines DD's hard work in single handedly creating a business, and giving an up bringing to Roshni. If she has been provided money in return then it is almost as if she has sold her daughter. And that takes away her self made woman claim and her "class" and "moral values."
Of course this is all speculation from my side. But even if this isn't the case, fact of the matter is that DD concealed this HUGE truth from Roshni for so many years. And although her marriage to Sid stands valid in a court of law, this isn't something you hide from your daughter. How can Roshni ever trust her mother again?
I don't know. But the two mothers in JR can never be redeemed in my eyes. Simran for bringing Patel clan on the road and forcing Sid to divorce Roshni. And now DD for lying to her daughter. And she's done it on more than one occasion. Irony is, she would taunt Sid over this! Bad mothers...not just bad judgement. Simply bad mothers!