The books that Shias quote, in those books tons of bad things are written against Hazrat Ali (RA) as well. But we sunnis, out of respect, keep our mouth shut.
In the books of history every thing is written. True or false regardless. But Ahle Sunnat wal Jamat do not bring them up because,
a). There is no need to. b). No proof of those riwayat. c). It is deadly to talk bad about those people and we lose adab which is deadly for Iman.
May Allah (SWT) protect us from such tests. Ameen