Denying Something Small, to Deny Something Bigger
In his book, Al-Istishraaq fi as-Seerah an-Nabawiiyah (Orientalism on the Prophet's Seerah), pp. 69-70, Abdullah Muhammad al-Ameen talks about how Watt denied that the Prophet (peace be upon him) would go to cave Hira for the sake of meditation and worship, but rather in order to escape the heat of Mecca.
Abdullah argues that Watt denies something small to deny something bigger, which is the Prophet's prior dedication to worship. This is to argue that he was an unlikely candidate for receiving revelation from God.
This is why we Muslims should never compromise on even the smallest of things, even if they are historical reports that, on the surface, have no real apparent inherent value. This is the game of these critics who try to push us away from the deen. They ask us to compromise on things that might appear very small, but they have more significant intentions than you may think.