Thanks for the play by play recap, though I'm not really sure it was necessary. He asked a question, I responded; though apparently not to your liking.
I would also strongly disagree that it is an ad hominem attack, as I am not attacking him, but his position. The best argument would have been that I was building a Straw Man argument or making an appeal to emotion, either of which I may have conceded, but certainly not an ad hominem attack.
The comparison of this position of refusing admittance to segregation is also a fair one, in my opinion. Now, just as then, many had strongly he