That could very well could be, so you ask for citations or you ask for clarification, or even say you're talking out of your ass; what you don't do is pull out singular anecdotes to make a case he's already conceded implicitly and think you're somehow rebutting anything. Rebutting a statical claim (i.e. most) with singular anecdotes is simply illogical, let alone one that's already been conceded in the question itself.
If I say most Asians have black hair, and you counter with I disagree because I've seen a blonde Asian; your rebuttal makes zero sense, it's fallacious.
If I say most Asians have black hair, and you counter with I disagree because I've seen a blonde Asian; your rebuttal makes zero sense, it's fallacious.