But the guy in original story I responded to had one specific concrete reason - if it is racism then solution does not help me. And I was supposed to find that understandable.
I was respousing to that particular logic of that particular guy who was much less reasonable then he believed himself. I was not responding to all the possible reasons of all the people in the world.
On the other hand, "the problem is racism" is very morally easy/acceptable in leftish circles, and saying the problem is anything else often gets a negative response (this thread existing might be counted as evidence here) - providing motivation to call things racism regardless of the truth of the matter... (This is not necessarily the case, of course - just trying to show that motivated reasoning goes both ways)