A strong preference can sound like evidence when the speaker never names it as preference.

Unnamed taste borrows the tone of fact. Someone says a design is bad, a neighbourhood is grim, a way of working will not scale, and the certainty in the voice does the job an argument would otherwise have to do. Often there is no dishonesty in it, only a speaker who has not noticed the line between what they like and what is true. The listener, given no marker, files the whole thing as information.

Try saying which parts of your own view are preference the next time you give an opinion. It sounds weaker for a second and makes everything else you say far easier to trust.