He doesn't go so far as to claim ignorance, only that,
[t]he Committee has obtained no evidence that Operation Fast and Furious was a politically-motivated operation conceived and directed by high-level Obama Administration political appointees at the Department of Justice.
Instead, Cummings settles for declaring that the administration did not conceive or direct Fast and Furious. He seems to think that justification hinges on such semantic differences.
Entitled "Fatally Flawed: Five Years of Gun-walking in Arizona," the report tries to lump Fast and Furious in with prior such schemes as Wide Receiver ("see? George Bush did it, too!"), and it attempts to portray the entire situation as something isolated to rogue elements in the Phoenix field division.
Of course, this flies in the face of facts. US Attorney Dennis Burke has resigned after being caught providing false claims to his superiors, and newly available documentation [pdf] from NPR shows that Assistant Attorney General Lanny Breuer and ATF Acting Director Kenneth Melson still approved of the operation's details as of February of 2011.