which itr to be filled

Why ITR 2 not applicable?

Instructions for filling ITR-1 SAHAJ................ A.Y. 2017-18

3. Who cannot use this Return Form
This Return Form should not be used by an individual whose total income for the
assessment year 2017-18 exceeds Rs.50 lakh or includes,-
(a) Income from more than one house property; or
(b) Income from winnings from lottery or income from Race horses; or
(c) Income taxable under section 115BBDA; or
(d) Income of the nature referred to in section 115BBE; or
(e) Income under the head “Capital Gains” e.g., short-term capital gains or long-term capital
gains from sale of house, plot, shares etc.; or
(f) Agricultural income in excess of ₹5,000; or
(g) Income from Business or Profession; or
(h) Loss under the head ‘Income from other sources’; or
(i) Person claiming relief under section 90 and/or 91; or
(j) Any resident having any asset (including financial interest in any entity) located outside
India or signing authority in any account located outside India; or
(k) Any resident having income from any source outside India.

Instructions for filling out FORM ITR-2

Who can use this Return Form?
This Return Form is to be used by an individual or an Hindu Undivided Family who is not eligible to file Sahaj ITR-1
and whose income chargeable to income-tax under the head “Profits or gains of business or profession” is in the nature of interest, salary, bonus, commission or remuneration, by  whatever name called, due to, or received by him from a partnership firm.

Who cannot use this Return Form?
This Return Form should not be used by an individual whose total income for the assessment year 2017-18 includes Income from Business or Profession under any proprietorship.

As per the instructions given by the department itself where is the logic for "defective-ness'' ?

Thanks