Even though we humans have lots of knowledge, we do not necessarily have a good and full theory of knowledge. Yet we should not let the lack of a good theory, deny the existence of what the theory should be explaining.
Humans have cognitive faculties with limitations. One can form snap judgments, but one can also recognize and pursue the objective principle of viewing as many perspectives as is necessary. One learns about one’s cognitive limitations over time, so one learns that to make a judgment about something beyond one’s immediate cognitive limitation, one needs to do extra work.