Truth isn't subjective. People's opinion of it is, but those are actually quite distinct statements.

From a "rights perspective" of morality, people certainly have the right to their opinions, as long as they don't act on them in ways that infringe the rights of others, and I've not made any argument to the contrary.

More to the point, a trust network doesn't really tell you what to believe. It only helps you do math calculations and make inferences based on what you tell it that you believe already. And if you don't like the results of the calculations, you can change the inputs you feed it (or even the algorithms it uses). It's a mental aid, like a calculator, not an arbiter of information.