Somehow this holds true. If you take a look on Altcoin Discussions, you can see a lot of Heroes or Legends spam all around. Yes you barely can find any valuable idea in their posts because they're just for filling up bounties' post requirements.
It was because of these type of posters the merit system was introduced. Most time, these high ranked accounts were bought just for the purpose of joining bounties or they are the alts which ranked up through spamming back when only activity determined your rank. When you see such cases, you simply report their spam post and move on as the moderators take care of that. There's nothing much you can do.
I was off the suggestion, when users having just airdrop merit have been reported for a certain amount of time as spammers, they get a reduction of airdropped merit (50 per 10 good report against them) demoting their rank. This will be the perfect punishment and might motivate them to change their posting habbit as they try to earned themselves some merit to rank up.