First of all, withholding an account value that everyone gets, whether it's called Airdrop or whatever, is stealing! Please keep in mind that I worked and invested for my steem balance. And now my balance together with the ninja stake can be found on the account which I have zero access to and influence, what is that?

secondly, if freezing Sun's stake from you was ok, then what Sun is doing now is ok too.
He's not doing anything different than what you've been doing.
There is only a little difference, he does it after you did it to him before, and you did it without any real reason. So you forced him to react.