According to verse 185 of Surah Baqarah, why can't the traveler fast?

Regarding the necessity of fasting on the journey, the Holy Qur'an in Surat al -Baqarah says: "You want it easy and it doesn't want it to be difficult."

Imam Sadiq (peace be upon him) quotes the Prophet (peace be upon him): "Iftar is a broken journey and prayer of divine gifts. Whoever does not pay attention to it has rejected the divine gift. "

According to this statement, perhaps one of the philosophies and wisdom of fasting in the journey is the same issue of discount on the task, and in other words, it is the expression of the servants.