Let me explain you the history of hadiths.
I will address the problem first.Prophet (SAW) during those days was like one in all leader of Arab. Apart from passing down the Qur'an he managed all the political and social needs to the best of his capabilities. He had thousands of followers. The problem started when his followers started to write down what Prophet said. And when he came to know that people are writing down what he was saying he said them not to.
It was narrated from Abu Sa’eed al-Khudri that the Messenger of Allaah (peace and blessings of Allaah be upon him) said: “Do not write anything from me; whoever has written anything from me other than the Qur’aan, let him erase it and narrate from me, for there is nothing wrong with that.” (Narrated by Muslim, al-Zuhd wa’l-Raqaa’iq, 5326)
You see... They wrote it down too.(* First mistake)
Hadiths are generally what Prophet spoke and lived in his lifetime but there are hadiths written like many years prior to the death of prophet. And there source is literally trust me bro. They start like- " I am the grandson of A who was a friend of B who was the follower of a man who followed beloved prophet."( Just an example ).
You see the problem here.
Now there were many groups and people who wanted to pollute the Islamic teachings. What they did is they wrote falsehood under the name of Hadiths and distributed it.
But they were handful.
The biggest hit came from the very own Islamic rulers. They made their Maulanas to write false hadiths and incite the common public's religious jingoism to send them in wars. This happened in 10-11th century and that is the time you see the invaded India. There was the first mention of 72 hoors 300 years prior to Revelation. And there were many more. You see these Ex- muslims who ' expose' Islam talk only about these false hadiths.
Now the question remains why people are not ready to change it. Well there was any attempt to do so. There was a scholar named Bukhari who separated good Hadiths from bad hadiths but there is a catch here. He was still a human and he lived in the medival times. He had his biases clear. He gave these hadiths authenticity stamps according to his own understanding ( or maybe some of his scholars for there time). Like banning music and all. These are pure bullshit. How can you attached attribute to something lifeless?
But why do people today are not ready to change it. Because The Quran explicitly tells us that hadith & sunnah which are Prophetic actions and words are extremely important to follow and hold on to as the entire practice of the Quran and how to live by it is in the life of the Prophet (sallAllahua alaihi wassallam). Since Allah (swt) ensures us in ‘Al Quran 15:09’ that He has protected the book from all corruption till the day of judgment therefore His above commandment to all believers to follow the Prophetic teachings and actions also hold exact same surety of protection.
( I copied an argument I saw a while back).
Because hadiths still contain a large part of Muslim culture. Not everything written their is wrong but some parts are acting like tumour for the whole religion.
The book free from corruption was only Quran Sharif not anything else. But people here think hadiths are also irrefutable.
Allah promised us to safeguard revelation but not man- made historical records( Yes that is what hadith is!)
People do not try to change it because it has been like 800 years and people have associated themselves from the sects which were forbidden in Islam. Because they are validated by many other scholars whom those Muslims place trust in. There are groups of scholars who have been validating these Hadith collections whenever they were collated. That’s why whole sects have developed which affirm to certain collections of Hadith.
Hadiths are important for Muslims. They contain the prescribed lifestyle for Muslims however it is still a man made product. Denying it's incorrectness is where the problem lies.