Are weak Hadith totally wrong?

‘Allama Haithami (May Allah shower His mercy on him) writes after mentioning 2 Hadith of the same meaning on the authority of Imam Tabarani:

 

Translation: In the chains of narration of both these Hadith, Rab’ee bin Badr is there who is a Forsaken Narrator.  (Majma Uz Zawaaid Wa Mamba ‘Ul Fawaaid Lil Haithami, Kitab Un Nikah, Babu Ma Ja'a Lil Waliyyi Wash Shuhood, Vol. 4, Pg. No. 526, Hadith No. 7520)

 

Also Hafidh Ibn Hajr ‘Asqalani (May Allah shower His mercy on him) has declared Rab’ee bin Badr as Forsaken Narrator.  (Taqreeb Ut Tahzeeb Li Ibn Hajr Il ‘Asqalani Dhikru Manismuhoo Raba’ah)

 

‘Allama Abu Ja’afar ‘Uqeeli (May Allah shower His mercy on him) has written in his book “Dhu’afaa” about Rab’ee bin Badr:

 

Translation: Imam Qutaiba has declared him unreliable.  (Adh Dhu’afaa Lil ‘Uqaili, Babur Ra)

 

‘Allama Haithami (May Allah shower His mercy on him) writes after mentioning another Hadith of Mo’jam Tabarani:

 

Translation: In this chain of narration, Suleman bin Arqam is there who is a Forsaken Narrator.  (Majma Uz Zawaaid Wa Mamba ‘Ul Fawaaid Lil Haithami, Kitab Un Nikah, Babu Ma Ja'a Lil Waliyyi Wash Shuhood, Vol. 4, Pg. No. 526, Hadith No. 7521)

 

Imam Nasai has included Suleman bin Arqam in unreliable narrators.  (Adh Dhu’afaa Wal Matrukeen Lin Nasai Babus Seen)

 

Imam Dhahabi (May Allah shower His mercy on him) has mentioned the opinion of the experts of Hadith criticism about Suleman bin Arqam in Meezan Ul ‘Itidaal:

 

Translation: The Hadith-experts have stopped narrating from him….Imam Ahmed says:  We don’t narrate on his authority.  Imam ‘Abbas and Imam ‘Uthman have narrated on the authority of Hadhrat Yahya bin Ma’een that he is unreliable.  ‘Allama Jauzjani said:  Suleman bin Arqam is Saqit Ul ‘Itibaar (Totally Unreliable).  Imam Abu Dawood and Imam Daraqutni have said that he is a Forsaken Narrator.  (Meezaan Ul ‘Itidaal Lidh Dhahabi, Babu Daal Taa Seen, Suleman bin Arqam, Vol. 2, Pg. No. 196)

 

In spite of so many objections and reservations on this Hadith, the non-followers deduce from it.  A question here is if the Marfu’ Hadith (Hadith whose chain of authority goes back to the Holy Prophet (Sallallahu alaihi wa sallam)) of 20 Raka’at of Taraweeh is weak and thus unacceptable, then how does the Hadith of 2 witnesses for marriage become acceptable to them in spite of being weak?