Is it bad? Yes. Is it annoying and spoils game experience? Yes. Still, it is a part of the game.
Besides, there's a bunch of popular maps that's force you to spawnkill because of how map is designed (ever so popular w00tabulous is prime example of that).
I don't even know wtf is that even is. I get the feeling that it's one of those things that is made-up by bitchy "pro"-players with inflated ego, heh.
If I understand correctly - it's shooting somebody in the back after passing them by or some shit? Well, it's also a part of the game, no? The whole "shooter" part in FPS stands for shooting.
Well, same deal like with spawnkilling and backshooting - it's a part of the game, whether we like it or not. Hell, even 1-on-1 duels of pros have occasional camping in it when they wait for powerup or health to spawn.
And that's where you wrong. You (AFAIK) can't wallhack through game tools, so, to use wallhack you'll have to use some third party software that is actively intrudes in the game process, so, it's not part of the game and thus you can't exactly put it in one pot with other things you've mentioned.
As for hoping - I'm kinda conflicted on that, because some people say it's just a part of physics of the game, and some say it's a bug in said physics. If it is a bug - then using it should be forbidden, but there's a problem of enforcing such restrictions and consequences of that enforcement. It's not like it's gonna scare away the average pew-pew pleb away from server, but if all the runners on server that used or using hoping gonna get banned - who's gonna grab the fucking flag?