This type of response is called moving the goal post. When someone responds to one claim, the claim is changed to something different which was not part of the original argument. This is debating in bad faith.

They were responding to a commenter suggesting it would produce completely unusable results, the question was never about whether the results produced would be redundant.

I know that any mention of fallacies, valid or otherwise, causes instinctive eye rolls, but in this instance I agree with them that this amounts to moving the goalposts.