True, but nobody has suggested that olympic bars start out rigid but get bent up through abuse.
That has been said of Powerlifting bars.
The whole question was: could someone squat 410kg with such minimal bar bend? The answer seems to be yes, with a high quality powerlifting squat bar, but certainly not with an weightlifting bar because of reasons given by others and yourself. Regardless, the squat is of course not really 410kg. The lifter is 75kg, and not particlarly thick. Had it been a real 410, he would have gone down and been lucky to ever get up from that squat!