Well Korra broke out of blood bending so your statement of only Mako breaking free is wrong. Itachi would Amaterasu Amon before he could blood bend. Azula, Katara, Toph, Iroh and even failure Korra > Amon.
Before Itachi have a chance to change to MS he get slapped down to the ground with the face down and then Itachi start of the flames and burn himself with the amatersus.
As well I didn't say that it was only Mako who could resist that. I said that Amon said that he was the only one who resisted it quite well.
By the way, Azula? Toph? Katara? Iroh? Yeah sure, dream on buddy

