There is nothing to blame: it means there is nothing to blame. It means that although there are shortcomings in speaking and doing things, there are still some advantages that should be understood.
From: The Biography of Han Mang by Ban Gu in the Eastern Han Dynasty. During the New Dynasty, Wang Mang carried out some reform measures, reducing the governors of the Western Han Dynasty to civilians and the surrounding minority kings to Hou. King Jumaqi refused to accept it and sent Lian Dan and Shi Xiong to attack Jumaqi. They forced civilian workers to increase taxes. Dr Feng Ying wrote to advise him not to waste people and money. Follwed fired him, and then felt that Feng Ying was right.
Idioms describing crows include: mob, love me, love my dog, silence, black magpies fighting for nests, black and white horse horns, black bass and so on.