Is it uncommon to focus on the things that support your counter argument in a discussion? Does one need to always "fairly" represent both sides when it's clear

Is it uncommon to focus on the things that support your counter argument in a discussion? Does one need to always "fairly" represent both sides when it's clear that there are obvious properties that you are not discounting? This is a discussion, and that was a single comment — I couldn't imagine people would see it as a comprehensive look at a topic as complex as types in programming. In that case, why not respond to the arguments I raise but instead attack what was never stated? I can see how part of the comment can prejudice you to an unbalanced opinion, but that's more on the reader than on the author — at least I think so.