Seeking Allah's Mercy
Qul HuwaAllahu Ahud!
Asalamo`Alaykum Wa Rahmatullahi Wa Barakaatuh,
Ayman bin khaled;104325 said:My beloved brother,Abu Seif;104324 said:Al-salam 'alaikum wa rahmatullahi wa barakatuh. If the Authentic Hadith reaches the Muslim, whether he is a follower of one of the Mathahib or not, he must act on it even if it contradicts his Mathhab. Islam did not start with the Mathahib, it started with: Allah said, His Messenger صلى الله عليه وسلم said. We ask Allah for guidance and steadfastness upon the Truth.
The statement you said, which is often said by many people of knowledge, is correct but people often, including some of the contemporary people of knowledge, seem not to be able to apply it in its context. To show you the fallacy of using this statement against Madhabs, let me give you one example:
One man was surfing different websites and came across a report that says, the Prophet ordered to do ghusl if one wash the dead and perform wudu if one carry the dead". So, he quoted the statement you have mentioned thinking he is following the Sunnah and does not understand this is an abrogated. The rulings require many conditions and laypeople and most people of knowledge do not have them today.
Most of the people of knowledge today who often advocate this statement lack knowledge in fiqh and cannot be called jurists. The people of Hadeeth before were jursits as much they were scholars of Hadeeth. But, today, people are nothing but the human version of google i..e they collect and do not understand the info they collected.