One reason those other games have less apparent hackers is: Cost; Free games are easy to reacquire under a new account; Hit them in the wallet, and they rethink their plans. Free to Play games are a softer target for such activity. It’s not BE it’s the proportion of hackers targeting a game.
Also Due in part to the perception that Unturned is a simple, kids game, people might target it to mess with less emotionally controlled players who have more “entertaining” freak outs to fuel their hacker lolz.
There may also be a age and maturity of the hackers factor, but I digress.