why show a mother so evil?

i know many people would disagree with me and hopefully some will agree but i want to know why are all the tv serials showing mothers as vamps? i understand that showing the female protagonist as a satti savitri bahu is compulsory in dramas but why butcher the character of mothers?
shweta has a lot of problems with avni and honestly speaking she is right regarding some issues but showing her as a villanous women who can go to any extent to kick avni out of neil's life even if it is at the cost of his own son's happiness and maybe sanity is not fair.
i agree that mothers usually get possessive of their sons when their sons get married (and i think that it is quite normal as sharing your kid with someone would be a bit difficult initially) but they(mom) dont go to the limit of spoiling their son's happiness(if he is happy with his wife) by playing dirty tricks with their bahus and scheming to throw them out of their son's life. no mother is that much insane at least i havent seen a family like that where mom's are so evil
i want to request writers to please not spoil a mother's image. believe it or not but dramas affect lives of people and continuosly showing mothers as horrible and wicked saas makes the society believe that mother-in-laws are very difficult to go along with

I agree worst thing that happened to Indian people is daily soaps