Perhaps you hadn't studied above authors and others to make these points on the basis of sound scientific knowledge, and this is what dispirited your listeners who were in real need of such clarification. Too bad you seem unable to have provided it. You know, even if you could still justify affirmative action and non discrimination (in addition to a non gassing and sterilization policy), your kind of argument does not remove the badge of inferiority a racialized minority is forced to wear simply through continuing suspicion that Levin and others may be correct.
And the very fact that you were not willing to rest your argument with the nonsense of the premises and assumptions (which you may have explained well) may well have implied to the audience you were not sure of your argument and therefore had to supplement it so you could win the debate--which is what it was for you, a debate.
Big deal, we get affirmative action, some may have thought, even though we may be racially inferior. And you wonder why some were angry, though you probably did not notice those who went despondent after the emotional violence of the evening.
Yours, Rakesh