I did not listened to entire video as the fallacy of the argument fell in few minutes after playing it.
Constitution is the basis of our democracy. According to that UNP got one seat. Our representatives to legislature are appointed through that. Hence Article 99A
'Every recognized political party or independent group contesting a General Election shall submit to the Commissioner of Elections within the nomination period specified for such election a list of persons qualified to be elected as Members of Parliament, from which it may nominate persons to fill the seats, if any, which such party or group will be entitled to, on such apportionment'
It is not mandatory to appoint National List members from the list as word 'may' only gives an option.
further, it states
'Where a recognized political party or independent group is entitled to a seat under the apportionment referred to above, the Commissioner of Elections shall by a notice, require the secretary of such recognized political party or group leader of such independent group to nominate within one week of such notice, persons qualified to be elected as Members of Parliament (being persons whose names are included in the list submitted to the Commissioner of Elections under this Article or in any nomination paper submitted in respect of any electoral district by such party of group at that election) to fill such seats and shall declare elected as Members of Parliament, the persons so nominated.
So Constitution is Explicit that any person whose name included in nomination paper can be appointed .
A Law cannot be Clearer than this. (the argument that Ranil could not be elected through preference is immaterial!) This is a legal analysis not a political one. Our constitution allows such person to be appointed to parliament this came through an amendment to constitution 14th and 15th amendments and these arguments I believe were considered at that time before allowing 14 and 15 amendments to go through! I do not think these lawyers (though looked old) were there when these arguments were considered by SC! when these amendments were challenged obviously Mr. Naganada was a Customs officer and may not have read the decisions even later!(in fact this point was argued by the lawyers for late MrsB who petitioned SC by more able lawyers such as late RKW, Gomin Dayasiri but rejected by SC as appointments were in terms of PR system under which the Constitution is made. This constitution recognized PR system over first past the post where individual gains recognition.