It's not just changing advice. It's refusal to acknowledge the false certainty with which the original advice was given, and that undermines any reason to trust

It's not just changing advice. It's refusal to acknowledge the false certainty with which the original advice was given, and that undermines any reason to trust the certainty with which current advice is being given. If the WHO had said in the early days 'We're 55% certain masks do more harm than good' and then said 'we've looked at more data and are now 60% certain masks do more good than harm', I doubt many of us would be clowning them to the degree we are. It's the fact they spoke as if they had 100% certainty in one direction and then as if they had 100% certainty in the other that gives the impression these people don't know what they're doing.