Attacking the source rather than the content is usually the mark of a poor debating position. If the content is good, the source doesn't matter. If the content is bad, the source's badness will be self-evident.
A debate is a formal event with rules. These are Internet comments. I'm not debating a position. I'm expressing myself. If you think my observation is nonconstructive, that's fine, but it's not because if I were debating I would have made a blunder, it's because we have different expectations and desires in this conversation.
That's fine, I'm just pointing out that your expression is incompatible with basic logic. Saying "this source sucks because x" does not address in any way what they actually said.