Because the intended sense is this: had it not been for the curse incurred by the Jews and Christians for turning graves into places of worship—a practice that necessarily involves building over them—his ﷺ grave would have been placed in an open, exposed tract of land. The Companions, however, did not do so, fearing that someone who came after them might build a mosque over it and thus bring the same curse upon themselves.

This is corroborated by the report recorded by Ibn Saʿd (2/241) with an authentic chain from al-Hasan—namely, al-Basrī—who said: “They consulted (1) about burying him ﷺ in the mosque. ʿĀʾishah then said, ‘The Messenger of Allah ﷺ had his head in my lap when he said, “May Allah fight those who turn the graves of their prophets into mosques.”’ Consequently they agreed to bury him where he passed away, in ʿĀʾishah’s house.”

I say: Although this report is mursal, it still indicates two points:

The first is that Lady ʿĀʾishah understood from the phrase “taking…"