I think this is ad hominem. His opinion is valid regardless of the fact if he likes you or not.
Yeah only if he actually stated why he disagreed.
You don't disagree with something just because you don't like the person who wrote it.
It's like if a guy proposes a bill to increase funding to a children's hospital, but the president vetos it because it was written by a man who is part of the anti-zionist movement.
Additionally, I didn't say his opinion was wrong, all I said was that he reason for disagreeing with the thread was stupid.