There is no malicious stakeholder in an anti-fragile system. And you don't need a 51% attack you just need an effective amount of stake, which is currently rather ~5-10%. How many of the Top20 witnesses are not voted for by Blocktrades: Zero.
At fist I thought you're joking, but it seems you don't. So let me put this straight. "Don't attack the network" has to be excluded from this list logically, because it's too vague. Those attacks, if cost effective, are mostly attacks on Apps directly or SPOCs in the nodes.
As soon as you fight back against what you call "malicious actor", you have made two mistakes already:
- If everyone is equal and the system is trustless, than bad and good actions are both valid to the same degree. Code is Law, everyone is equal.
- You don't fight back, you let em buy in and Judo move them out. You have to thrive and become stronger with opposition, not fight them.
Maybe tune into Community Token Talk from time to time. Dan is the best person to explain things like this. He's a decentralization wizard.