The response to that objection also seems pretty bad. Sure, some humans do not have the prerequisities to do e.g. image recognition, but they have the intellectual ability to do so. A person detached from all their senses and means to express himself is not less intelligent than GPT-3, just because GPT-3 has the ability to consume input and produce output. In fact, by the standards of the article, such a person would be outclassed by any computer programm. And for the second response, saying that GPT-3 could potentially also deal with images or sound, if presented in the right format is just proof that it is not general. Saying maybe it could do more things if we train it on more things is just blind speculation. It could very easily be the case that if you tried to implement sound input in GPT-3, it would significantly worsen it performance on all other tasks.
Besides, doesn't GPT-3 still struggle very much with continuity and producing output that is coherent over long spans of text? I am not sure if there is any one good test to judge the literary abilities of AI, but surely long form writing has to be included before it is judged as equivalent...