there's a huge, fundamental difference between silence and (very) low quality discussion.
silence totally blocks progress.
low quality discussion, if continued persistently, is actually fine.
in programming terms:
b/c the low quality discusser is exposing an API with various convoluted, messy, buggy, misnamed, falsely documented functions which people he's talking with can access.
universality is so easy to come by, even with a very limited array of bad functions.
another analogy is a hacker will simply find a buffer overflow in your API and then root your system and be able to install whatever software he wants.
what stops the meta-API approach or the security hole approach? silence. you can't get anywhere with an API that stops answering queries. you can't root a box that ignores all incoming requests.
if you're dumb but persistent, good discussers can figure out what you suck at and what can work, and start to focus in. they can try a variety of things, learn about how you block them, and then keep trying new workarounds (each time either discovering a new block or directly making progress). they have something to work with, like a puzzle to solve.
but if you're silent, they can't do a damn thing. if you keep dropping discussions, they can't help you.
persistent bad replies make a WHOLE WORLD of difference, vs silence.