Who Is The Quran Addressing?
Also the ayah says ‘kitaaban mawqutaa’. This could be taken to mean that this is the time that prayer was scheduled and that is when they can attend certain prayers
Praying is an integral part of believe in God, it is against the very human nature to believe in God and not feel the need to pray to Him. Praying is an extension of the ‘Believe in one God’ fact, separating the two would be illogical and against the human nature itself. You cannot take an exception and use it as an argument against the general principles. In most of the world, prayer timings can be followed with ease and in case an exception arises, guidance available in Quran and Sunnah would be used for exceptions, and if not, ijtihaad would be used. But nullifying a directive of religion based on an exception is against rationality.
It is through Sunnah initiated by the Prophet (sws) transmitted to us through tawatur of centuries.