As much as possible, I avoid trying to hurt other people. But if saying the truth will hurt, I weigh it first before telling but more often than not, I say it. Especially if hurting the concerned person by the truth will protect them from further harm.
But truth being the truth is not always necessary. In fact, there are lots of truths around us that we haven't discovered yet but here we are living off without knowing.
Truth frees and protects people. And it hurts. But sometimes, as unnecessary as it is, people utilize truths wrongly as an excuse to hurt others.
It's different between trying to help other people by stating the truth than trying to destroy someone using it. The difference between the two is the intention. The first one is mainly to tell the truth. The other one is to hurt.