This is a problem that is as old as time, and isn't present in Willard alone. There's always been somewhat of a pro-Combine stance in WN (if you don't think this you are delusional + take your meds) but I feel like the scales have been evened out enough that at least when the PK criteria were somewhat equalized.
Still, the cause is quite simple, and has been outlined multiple times in this thread already: you can lose months of progress if your character gets PK'd, and due to the strict nature of the PK criteria, it is very, very easy to get PK'd. Not playing to win goes against any instinct a normally functioning adult has that tries to find a proper balance between having fun (roleplaying, combat) and having a little less fun (rank grind, item grind, etc.). When I backed the idea a year or so back I thought it might could've posed some magic fix that would solve all outlying issues the server had (mainly the Combine bias, which was a great deal bigger than now) but instead, it appears that it just poisoned the well and caused a new problem of its own.
The only advice I can give is try something new. Maybe reverse the entire idea of strict PK's, and go with something more lenient for *everyone*. Hell, it would make combat more interesting at least, and might solve some of the try-harding. It doesn't need to be permanent, but it's an idea that Willard hasn't really delved in too deep from what I remember, and it might improve things.
And yes, I know I haven't played for over a year.
And no, I don't care. Also, I'm right, so cope.