My question is this; can you still call yourself a decent person if your go to response is seemingly always silence? Why is it those voices only ever pipe up when it's time to defend themselves against the accusations rather than defend others during the trolling?

Unfortunately, by engaging the trolls all you are doing is encouraging them. What any troll wants, craves and needs is attention and when you give it to them, they are emboldened.

What much of this is about is context. When you are using a site, or even in real life when you are at a place that begs a certain type of behavior, you ought not be shocked when you see it. If you go to rock concert you'll see people being loud and raucous. Those same people will be quiet and calm when in a library. So much of the way people behave themselves has to do with their surroundings. Online is no different. If the norm seems to be people yelling and arguing, then you are more likely to argue and yell. If the norm is to discuss in a thoughtful way then you're more likely to do that.

Trolls need food. Don't feed the trolls. You have nothing to gain by it. You will not change their mind. If anyone is ever trolled here, I highly recommend using the tools we have provided and not engaging.

EDIT: if you do engage a troll, I think you need to ask yourself why you did that? Trolls are a problem, yes but those that engage the trolls and actively combat them can also be responsible for diminishing the integrity of a community. The "anti-troll" sort of becomes a troll via enabling. (End edit)

As for whether or not people are inherently decent, I tend to think that they are ...when their environment sets the expectation that they ought to be so. To a varying degree, we are all subject to the pressures of our surroundings. This is why it's so important to surround ourselves, IRL and online with those that share our general values. -We may have differing thoughts on politics, religion etc but if you can share those thoughts in a civil way, I'm all good with ya. If you cannot.... You're heading to "ignore island."