Evidence deserves more authority than the person presenting it.

Who is speaking affects how likely a claim is to be worth checking; it does not determine whether it is true. Confident, credentialed, and well-liked people are wrong regularly, and disliked or unimpressive ones are right regularly. Letting the speaker settle the matter means your beliefs track social standing rather than reality.

When something important is at stake, separate the two questions. Would I still find this convincing coming from someone I dislike, and would I still doubt it coming from someone I trust. If the answers differ, you have been assessing the person rather than the evidence.