This has been my experience, too, as well as people who understood The Science perfectly and that the authorities were just taking a best guess early on, which set them further against any kind of mandate. (Mostly older, conservative physicians with an "it'll be fine" attitude)

The Science didn't change that much (viz: masks in healthcare since forever), but the flip-flopping with messages ("don't horde masks; they won't save you!", "wait, no - everyone needs a mask!"), which was really less about The Science than about different concerns (mask effectiveness, availability) were just the "I told you so" they were looking for.