I don't think it's true. It's a shia hadith. You can tell by the (as) after "Ali". Shias use 'alayhi salaam' with ahlul bayht where as rest of the muslims use 'alayhi salaam' for prophets only.
Dear Shahid Sahab,
The Hadith regarding comparison of Hazrat Ali [May Allah be pleased with him] with Prophet Aaron [PBUH], Prophet Mohammad [PBUH] and Prophet Moses [PBUH] was narrated:
THE MERITS OF 'ALI B. ABI TALIB (ALLAH BE PLEASED WITH HIM) [Sahih Muslim]
The narrations below were narrated by Hazrat Saad Bin Waqas [May Allah be pleased with him] and his son Amir. Hazrat Saad was maternal uncle of Prophet Mohammad [PBUH].
1- Amir b Sa'd b. Abi Waqqas reporte (l on the authority of his father that Allah's Messenger (may peace be upon him) addressing 'All said: You are in the same position with relation to me as Aaron- (Harun) was in relation to Moses but with (this explicit difference) that there is no prophet after me. Sa'd said: I had an earnest desire to hear it directly from Sa'd, so I met him and narrated to him what (his son) Amir had narrated to me, whereupon he said: Yes, I did hear it. I said: Did you hear it yourself? Thereupon he placed his fingers upon his ears and said: Yes, and if not, let both my ears become deaf.
2- Sa'd b. Abi Waqqas reported that Allah's Messenger (may peace be upon him) left 'Ali b. Abi Talib behind him (as he proceeded) to the expedition of Tabuk, whereupon he ('Ali) said: Allah's Messenger, are you leaving me behind amongst women 4nd children? Thereupon he (the Holy Prophet) said: Aren't you satisfied with being unto me what Aaron was unto Moses but with this exception that there would be no prophet after me.
3- Sa'd reported Allah's Apostle (may peace be upon him) as saying to 'Ali: Aren't you satisfied with being unto me what Aaron was unto Moses?
NOTE: Rafizi accept these Hadith about Hazrat Ali [May Allah be pleased with him] but I fail to understand is it possible that the son of Hazrat Saad i.e. Amr Bin Saad was shown by the same Historian Tabari through 'doubtful' narrators as the Leader of the Syrian Army [under the orders of Ubaidullah Bin Ziyad bin Abu Sufiyan (Ziyad had served as Governor of Persia under Hazrat Ali - May Allah be pleasede with him)] sent against Hazrat Hussain [May Allah be pleased with him].
Abu Mikhnaf [The Liar Rafizi Narrator whose narrations were the major part of Tabari's History regarding Jamal, Siffin, Neherwan, and Karbala] in his separate book "Maqtal Abi Mikhnaf" (Urdu Translation published in Hyderabad Daccan India] has also reported that before the main 'battle' of Karbala, Huzrat Hussain and Amr Bin Saad [relatives] were discussing something without anyone with them.
Nobody questions Tabari and Mikhnaf as to what were they discussing before the 'alleged massacre'.?