^ ok - primarily the quran was revealed specifically in response to problems faced by the prophet (saws), in order than the islamic state be succesfully established.
but most of these rulings/advices also apply in general.
sometimes a narrative is given eg: the events at the battle of Uhud. - but we can derive lessons and benefits which are timeless eg obediance to the ruler, courage in the face of the enemy etc
also eg surah kafiroon - this was revealed specifcally in response to an event in the prophets life where the quraysh tried to get him to compromise on the religion by striking a deal with him. they said they would become muslim for one day and then the prophet worships idols for one day - so the surah came in response to it. - yet it has a message for us regardless.
it is also true that some verses are extremely specific, and if you have commentary of the quran it becomes clear that they refer to a time in the prophets life. also they are one of the basis for deriving rulings/shariah
ok the "contradictory explanation" - the prophet was the last to emigrate and until he did so the verses became stronger and more towards become obligatory - so when the prophet emigrated it became obligatory to emigrate
and the verse was abrogated as a matter of historical fact (according to the video) which makes sense because there is no need to emigrate after makkah is conquered ie there is no longer a fear of persecution
i hope that answered ur question...