Anyone who has their transactions "banned" by pools will simply pay enticing enough fees to have other miners include their transactions. OP seems to ignore financial incentives when speaking about banning Bitcoin. If there is money to be made, people will route around any regulations. This has been proven over and over again in the history of the world.
A few questions.
If people have to pay high fees to get their transactions confirmed, why would they use Bitcoin rather than some competing form of money transfer?
If the the hashrate of miners including blacklisted transactions shrinks to insignificance vs. those who adhere to the blacklist, surely it doesn't matter how high the fees are? Those transactions could take weeks/months/years to confirm, depending on what percentage of the overall hashrate the adhering farms represent.
Actually they would never confirm, because the 50% hashrate could blacklist the minority hashrate. This hints at franky1's logic error.