This is not a flaw and we are well aware of this type of attack.
From the whitepaper, section 5:
"It is possible that the rewards will also be split to include a moderator role to help ensure that the network runs optimally and to prevent anti-spam attacks."
There is a
gigantic flaw in WhaleCoin: it supposedly limits the upvote power to the same amount for any whale with more than 1000 coins. However nothing prevents a whale from splitting their coins into multiple accounts with 1000 coins each.