Because as we will explain completely later...

Because as we will explain completely later, in some times which Shiite were under the pressure Imams (a.s.) forgave the Khums or part of it and practically Khums had forgot for a period of time, therefore when conditions were normal and Khums had to be taken, lots of Shiites were uninformed about the quality of that and it is not a strange or unusual matter.

Also today, there are lots of people who have not enough knowledge about the issues of the Khums, even oppositions who object this much about that have limited information about Khums.

3- کتب الیه ابراهیم بن محمّد الهمدانى اقرأنى على کتاب ابیک فیمـا اوجبه على اصحاب الضّیاع انه اوجب علیهم نصف السّدس بعد المؤونة، بانّه لیس على من لم یقم ضیعته بمؤونته نصف السّدس، و لاغیر ذلک، فاختلف من قبلنا فى ذلک فقالوا: یجب على الضّیاع الخمس بعد المؤونة، مؤونة الضّیعة و خراجها، لا مؤونة الرّجل و عیاله فکتب: و قرء على بن مهزیار علیه الخمس بعد مؤونته و مؤونة عیاله و بعد خراج السّلطان Ibrahim ibn Muhammad Hamedani wrote to Imam (a.s.) that: Ali (Ibn Mahzyar) read the letter of your father for me that it had been ordered in the letter that owners of water and land should pay one twelfth of their income after subtracting their costs to his holiness, but persons who their water and estates do not suffice their costs, this is not obligatory for them, neither one twelfth nor other than that; people who are here with me have disagreement and discussion about this matter, they say that Khums of income is obligatory on water and land, and this is after subtracting the costs of water and land themselves and their tribute, not the costs of person himself and his wife and children.

“Imam wrote his answer and Ali ibn Mahzyar also saw the letter that, Khums is necessary for this person after subtracting the cost of living of him and his wife and children and after subtracting the tribute of government”.