Are weak Hadith totally wrong?

The unreliability of the later narrators does not affect Imam Azam Abu Hanifa’s opinion

The research of narrators, etc. is necessary for those who have deduced from those Hadith in whose chain of narration some unreliable narrator (Rawi) is present.  If some Hadith-experts consider that particular narrator as unreliable, even then the deduction of Imam Azam Abu Hanifa is not affected by this, because Imam Azam (May Allah shower His mercy on him) is among the 5th class of the narrators (Sighar Taba‘een).  He passed away in 150 Hijri.  It is obvious that the unreliability that seeps in the later ages does not affect the opinion of the earlier masters.

Imam Abdul Wahab Sha’araani (May Allah shower His mercy on him) says:

Translation: If any deduction of Imam Azam’s school of thought is considered unreliable, then this unreliability is of the narrators who come into the chain of narration after Imam Azam.  (Meezan Ush Sharia’til Kubra)