VW belongs to Porsche.
I don't think environmental norms are looked at for the race, neither a program to play with emissions.
Note that in GT AM, Porsche won also with the 10kgs weight.
I believe there were a lack of chance for Ford, especially when safety car went on the track at the same time the Ford GT (1rst at the time, just after having overtaken the 2 Porsche - Allez Sébasien Bourdais!) was at the pit lane. Same lack of chance with other safety cars and yellow flags time during the rest of the race.