This fellow sounds like he must be an undergrad, or a non-psychologist.

Thank you for that cogent ad-homimen argument!

No-one believes that the area traditionally defined as Broca's area is the only frontal area involved in language processing or even in Broca's aphasia, and even less for Wernicke's.

Which is why I never said that anyone believed that. It is common for damage to a number of different, often nearby, structures, to cause similar symptoms. It's common for it to be difficult to distinguish symptoms caused by different underlying damage.

In the case of Broca's area and Wernicke's area, however, it's more than that. There is strong evidence that damage to Broca's area does not cause Broca's aphasia (while damage to numerous other areas does); and damage to Wernicke's area does not cause Wernicke's aphasia (though damage to numerous other nearby areas does).