One is doing something wrong with this evidence if one updates against improved health outcomes for public health insurance for the poor (i.e. Medicaid).

Updates always move you towards what you just saw, and so if your estimate was above what you just saw, you update down. If you only consider the hypotheses that Medicaid "improves," "has no effect," or "harms," then this is weak evidence for "improves" (and "has no effect"). But a more sophisticated set of hypotheses is the quantitative effect of Medicaid; if one estimated beforehand that Medicaid doubled lifespans (to use an exaggerated example), they should revise their estimate downward after seeing this study.