At the risk of getting tarred and feathered here, I'm gonna say I agree with him. But - you have to put it into context.
If you only had that amount of money and you needed ONE car, then getting the Fiesta would probably be a wiser choice, (newer, 4 doors etc.), so when he says the M3 would probably be more expensive to run and a better weekend car then he is probably right.
If you start questioning why a Fiesta is being compared to a M3 on a performance basis, then yes, things start to fall apart.