Moyhu should be pointing at the supporter for costing them a goal not the umpire.
Having watched Moyhu against Tarra last week there were two Hoppers supporters close by yelling out to one umpire all day long and calling him by his name. While none of it was offensive language or threatening, it was unnecessary and overly personal criticism.
Obviously it's difficult when you are passionate about supporting your team, but think before you talk and let them do their job. If you're that convinced you could do it better get out there and do it!