Faiz Ahmad says saying the prophet was illiterate is disrespectful and a literacy flaw, however when we read this hadith in Bukhari, Narrated By Ibn `Umar: The Prophet (ﷺ) said, “We are an illiterate nation; we neither write, nor know accounts. The month is like this and this, i.e. sometimes of 29 days and sometimes of thirty days.” (Sahih Al Bukhari 1913).
We know the prophet was illiterate in the sense that he could not read or write, so this belief of his clearly goes against the words of The Prophet ﷺ.

Translation: Faiz Ahmad Owaisi said: To say that the Messenger ﷺ was “illiterate” is both a literary flaw and an act of disrespect. The correct meaning intended in relation to the Messenger ﷺ should be that he was unlettered in the sense of not having learned from any human teacher, not that he was ignorant or devoid of knowledge.
The word “illiterate” implies being devoid of knowledge, which is completely inappropriate for the Messenger ﷺ. The proper understanding is that he did not become learned by reading from others, but was granted knowledge directly by Allah.
Later, Maududi did write what we have said, in his Tafhim al-Quran from volume 14 onwards, using the word unlettered in this accurate sense. However, from the beginning of Surah Salah to the start of volume 15, he made errors in this matter. This humble one is only pointing this out in relation to that.
Parha Likha Ummi Nabi, Page 55
