One of the keys to the strategy they used successfully to destroy voat was to scare off new users. Whenever there was a major subreddit banning on reddit, a bunch of fake racist/pedo/nazi whatever accounts that had barely posted for months fired up and went into overdrive. My suggestion, unpleasant as it may be, is to moderate the front page to some degree, and try and cultivate a TRUSTED base of mods for major communities to do the garbage work to stop the trolls in them. In my opinion, trying to cultivate a culture and a sufficiently large userbase that their shit is kept off the frontpage would, if nothing else, give a good idea of how large an org they have, if they scale up their efforts with the site's userbase.

On that last point, last I checked, one of the only voat communities that didn't get destroyed by the racist and pedo trolls was FatPeopleHate. They managed to keep the trolld mostly out despite whatever else was going on by having relatively heavy censorship of things unrelated to hating fat people, and a policy that required moderator appeals to be accompanied by a timestamped picture to prove that they weren't fat. I'm no fan of FPH, or of censorship, but it's interesting to see that strange policy seemed to keep the trolls out, almost inadvertantly.