I believe that many people don’t even know that using Discord is problematic. So just saying that it shouldn’t be used can be enough to – in combination of other messages they may get – make a difference. Being a jerk is not the goal, obviously, but nor is me being seen as a jerk important at all.
You might say that my jerkness prevents people from believing me. But it seems to me from looking at the behavior of activists and their tactics that nobody cares about that.