why people have started rejecting ahadees these days

Re: why people have started rejecting ahadees these days

here is one...

The Qur'an says:

15:9 Behold, it is We Ourselves Who have sent down this Reminder, and behold, it is We Who shall truly guard it. (6:115).

But numerous Hadiths in six famous Hadiths books makes the protection of Allah as promised in 15:9, doubtful. Of course one can't reproduce all those Hadtihs here therefore see a glimpse below.

Sunan Ibn-I-Majah Vol III Chapter 36 (Suckling of a young boy) Hadith # 1944

A'isha (Allah be pleased with her) is reported to have said, "The verse concerning stoning the fornicator to death *(Rajm) *and ten sucklings of a young man have been revealed. Indeed it was recorded on a piece of paper lying under my cushion. When Allah's Messenger (Peace and blessing of Allah be upon him) breathed his last, we were occupied with his death when a domestic goat entered and ate it up."
We don't see any verse in Qur'an relating to "Rajm" and "ten suckling" according to Ibn-e-Majah, these verses were revealed but a domestic goat ate them up while Allah is saying "We who will truly guard it."
Why did Ibn-e-Majah record this fabricated story in his Sunan? Was he not aware of 15:9? Or was he among those making the completeness of Qur'an doubtful?