Paul here, 1/2 of the CC dev team.
TSG is inspired by Harvest and we are happy to credit Oxygene. We did not set out to clone the game but put our own spin on the game play and extend it into new areas. Since creating DTD and FETD (two of the most heavily cloned flash games) we have a great deal of experience of people cloning our games. But we recognise that we didn't invent the TD genre (nobody did, it grew by extending mods of Starcraft over many generations) and that the game industry is built on such iterative improvement.
If you guys are not making waaay more than $20K (the example you gave for a flash game) on Harvest it would be a crime as it's a cracking game. Hopefully we can send some business your way.
For the record, we didn't make the 'man baby' posts