Why is tunneling bad?
Survivors need to escape the killer. The killer needs to kill the survivors. If the killer goes after you, despite you just have being unhooked recently, he is basically just forcing you to literally play the game. Running away from the killer IS the game. Why is that considered bad? Being forced to play?
I hear people say that it's bad because it shortens the survivor time in the match. Now, what you do the majority of the time that the killer is NOT going for you? You press your mouse button for a couple of minutes while staring at a gen. When I play survivor, I like whenever the killer comes for me because it means I will actually have some action and test my looping skills against the player playing killer. If it keeps coming after me it's even better. Said that, it bugs me why would any survivor say "Hey, killer, stop coming for me and let me stare at this gen for a couple of minutes."
Want you or not, looping is the majority of a survivor's gameplay. You shouldn't be mad that the killer is playing the game and forcing you to do so too.
And I'm not talking about tunneling in the sense of the killer downing you immediately after you got unhooked, because unless it was camping, it is entirely your teammates fault.
Please, maybe I'm seeing things the wrong way, so tell me why is it so bad that the KILLER keeps coming for you?