My comment was substantive. Saying that "X person who is Z has Y opinion" without giving any reasons - stats, sources, etc - why they have that opinion is what is unsubstantive.

My friend, who is a dietician, thinks that chocolate is healthy.

Great, but why does anyone care what my friend thinks? The word "dietician" doesn't make their opinion any more valid because there's zero additional data in that sentence to back up the opinion. So it's a useless opinion presented as-is in a comment with no justification.

So could you please stop posting unsubstantive comments on hacker news?