A character assassination would be something like "He does something morally reprehensible (cheating, selling ads to three year olds, etc". The above post is more like "He harps on multiple things he maybe shouldn't, and has an outraged user-base he keeps stoked, so that should be taken into account."
If I said, "I find his voice really grating and his outrage mostly makes me dislike him" that isn't a character assassination- just my opinion he is unlikeable.
If I said, "I find his voice really grating and his outrage mostly makes me dislike him" that isn't a character assassination- just my opinion he is unlikeable.