For the record, the objective of town is to kill scum, how much attention you grab doing it is irrelevant. Town will defend themselves when necessary cause you don't want any confirmed town to die, but if no scum lynches happen, town loses by default because they're on a timer, every no lynch is a free scum kill but a town lynch is a faster route to endgame. So town needs to be pro-active and do what it takes to kill scum, only caring about self-defense if it's necessary to prevent a confirmed townie (to the townie, themselves) from dying.
There are finer points of putting this into practice, especially when you consider strong PRs, but the fundamental weakness that scum has is their priority is survival, town reveals scum by showing their priority is survival over killing scum. Of course, there are ******* town that do this too, but part of being a good townie is to recognize whether somebody is being dumb or scummy.