Certainty borrowed from somebody else is still borrowed.

Confidence adopted from someone else has no more grounding than your own examination gave it. Repeating a position with the certainty of the person you got it from means carrying the conclusion without the reasoning, and it will not survive the first serious question. This is how confident groups end up sharing a belief nobody in them has actually verified.

Before you assert something you picked up from a source you trust, ask whether you could defend it yourself. If not, say so when you repeat it. There is nothing wrong with relying on others; it is only worth being clear when you are.