Responding to an unambiguously wrong referee comment I'm now replying to a referee. One of his points is unambiguously wrong. Moreover, without going into specifics, he spends a lot of time on that point and asks us to do something with our framework that it cannot address. This is not stubbornness on our part since otherwise we'd be happy to accommodate requests.

But I’m terrified of writing "This comment is wrong". Even if I thereafter go into some detail as to why it's wrong, somehow I fear a backlash which we know shouldn’t be a reaction of referees but often can be. 

Does anyone have any advice?
One is allowed to, and in fact often should, respectfully disagree with parts of a review. However, stay a mile clear from the phrasing "this is wrong". Note that even if the reviewer made an objectively wrong comment, you need to respond with the assumption in mind that this happened due to an honest misunderstanding on his part, and not in bad faith.

Hence, a better phrasing may be:


  We disagree with Reviewer 2 on this comment. While we show that our framework is able to do A and B, it is by design not able to do C. We understand that this was not clear enough to the reviewer, and have rephrased our motivation to make this point more clear.


Note how this phrasing does not "give in" to the reviewer, but acknowledges that part of the blame about such misunderstanding lies with the authors. Also note that you do some text changes based on this review, which I have found to generally be a good idea. I have the impression just saying "the reviewer misunderstood; we are not changing the manuscript" leaves a bad taste in the mouth of many editors.

The reviewer may in theory still insist that without C, your framework is without value, but that really cannot be helped if your system just does not do C.