they left because tron is attempting to centralize steem. the community witnesses are trying to keep steem owned by everyone. justin managed to convince exchanges, including the korean huobi, to use the money of people on exchanges to powerup and vote for justins own witnesses.

So we need the korean community to remove all money sitting on exchanges, and use all of their 30 witness votes for witnesses not running 22.5. under the hood everyone is running now 22.1 but the witnesses running 22.5 are justins witnesses and justin is planning to give more power to exchanges by giving them special rights for powering down quickly which will increase their ability to use peoples money for voting, and the ability to quickly buy or sell steem increasing the volatility of steem.