Maybe it’s neither honest nor dishonest. To make the judgment about “self-deception” is to assume they share your value about what rigors a belief should have to pass through before it can be considered a true belief. If they don’t share that value then they’re neither consciously nor unconsciously intending to deceive themselves.
It can be honest (naivety), dishonest or something else, depending on the circumstances. If it is something else, it may not be a faith based belief...a conviction of truth regardless of absence of supporting evidence, and even in the face of evidence against the belief.
People in the middle ages who held a conviction in a geocentric solar system, for example, were not necessarily engaging in self deception, just flawed assumptions based on surface appearances, sun rising and setting over the horizon, etc. That became self deception and dishonesty when evidence for Heliocentric solar system became available, yet was suppressed by the Church in order to maintain dogma.
