I can't see how making that statement undermines the rest of the argument. It would help if you could clarify that relationship.

And I'm not sure I understand why, if you can't distinguish them, the distinction is unimportant. It's hard to distinguish an edible mushroom from a poisonous one and yet making that distinction makes a huge difference.

Interviews are definitely a limited tool to do so btw, this is only something that you realize over time. It's also very easy to play an interviewer if the interviewee's soft skills are better than the interviewer's (which happens often in this industry).