This is a weak view that clashes with those authentic ḥadiths.

Al-Ṭaḥāwī tried to rebut them with what he recorded in al-Mushkil, where he said: “ʿAlī ibn Abī Shaybah narrated to us; Yazīd ibn Hārūn narrated to us; Ḥammād ibn Salamah, from Ḥakīm al-Athram, from Abū Tamīmah al-Hujaymī: I heard Abū Mūsā al-Ashʿarī say:

‘I will not allow anyone to look at a female slave except at what is above her navel and below her knees. If I learn of anyone who does otherwise, I shall punish him.’ (1)

Abū Jaʿfar [al-Ṭaḥāwī] then remarked:

‘In light of what we have mentioned, it is permissible to oppose the earlier ḥadiths that contradict this report with this very report.’

By the phrase ‘what we have mentioned’ he refers to his introductory words about this narration, namely:

‘We found that Abū Mūsā al-Ashʿarī uttered a statement in which he combined his words with a threat against anyone who differed with him—something that could not have been said purely on the basis of personal opinion, for threats are not issued concerning matters that rest on individual reasoning, matters in which another person could legitimately hold the opposite view.’

As you can see, he maintains that although the report is mawqūf (stopping with the Companion), it nevertheless has the standing of a marfūʿ narration because it contains a threat—something he claims cannot be said on the basis of mere opinion. This, however, is not a necessary rule in legal questions, for it is permissible to attach a threat to an issue arrived at through individual ijtihād, even though the person may in fact be mistaken.